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2024-09-26netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTEDPhil Sutter1-1/+1
Fix the comment which incorrectly defines it as NLA_U32. Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend") Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2024-09-14net: fib_rules: Add DSCP selector attributeIdo Schimmel1-0/+1
The FIB rule TOS selector is implemented differently between IPv4 and IPv6. In IPv4 it is used to match on the three "Type of Services" bits specified in RFC 791, while in IPv6 is it is used to match on the six DSCP bits specified in RFC 2474. Add a new FIB rule attribute to allow matching on DSCP. The attribute will be used to implement a 'dscp' selector in ip-rule with a consistent behavior between IPv4 and IPv6. For now, set the type of the attribute to 'NLA_REJECT' so that user space will not be able to configure it. This restriction will be lifted once both IPv4 and IPv6 support the new attribute. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20240911093748.3662015-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-13uapi: libc-compat: remove ipx leftoversJakub Kicinski1-36/+0
The uAPI headers for IPX were deleted 3 years ago in commit 6c9b40844751 ("net: Remove net/ipx.h and uapi/linux/ipx.h header files") Delete the leftover defines from libc-compat.h Link: https://patch.msgid.link/20240911002142.1508694-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-12net: ethernet: oa_tc6: implement internal PHY initializationParthiban Veerasooran1-0/+1
Internal PHY is initialized as per the PHY register capability supported by the MAC-PHY. Direct PHY Register Access Capability indicates if PHY registers are directly accessible within the SPI register memory space. Indirect PHY Register Access Capability indicates if PHY registers are indirectly accessible through the MDIO/MDC registers MDIOACCn defined in OPEN Alliance specification. Currently the direct register access is only supported. Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com> Link: https://patch.msgid.link/20240909082514.262942-7-Parthiban.Veerasooran@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-12netdev: add dmabuf introspectionMina Almasry1-0/+2
Add dmabuf information to page_pool stats: $ ./cli.py --spec ../netlink/specs/netdev.yaml --dump page-pool-get ... {'dmabuf': 10, 'id': 456, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 455, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 454, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 453, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 452, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 451, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 450, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, {'dmabuf': 10, 'id': 449, 'ifindex': 3, 'inflight': 1023, 'inflight-mem': 4190208}, And queue stats: $ ./cli.py --spec ../netlink/specs/netdev.yaml --dump queue-get ... {'dmabuf': 10, 'id': 8, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 9, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 10, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 11, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 12, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 13, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 14, 'ifindex': 3, 'type': 'rx'}, {'dmabuf': 10, 'id': 15, 'ifindex': 3, 'type': 'rx'}, Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-14-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-12net: add SO_DEVMEM_DONTNEED setsockopt to release RX fragsMina Almasry1-0/+5
Add an interface for the user to notify the kernel that it is done reading the devmem dmabuf frags returned as cmsg. The kernel will drop the reference on the frags to make them available for reuse. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20240910171458.219195-11-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-12tcp: RX path for devmem TCPMina Almasry1-0/+13
In tcp_recvmsg_locked(), detect if the skb being received by the user is a devmem skb. In this case - if the user provided the MSG_SOCK_DEVMEM flag - pass it to tcp_recvmsg_devmem() for custom handling. tcp_recvmsg_devmem() copies any data in the skb header to the linear buffer, and returns a cmsg to the user indicating the number of bytes returned in the linear buffer. tcp_recvmsg_devmem() then loops over the unaccessible devmem skb frags, and returns to the user a cmsg_devmem indicating the location of the data in the dmabuf device memory. cmsg_devmem contains this information: 1. the offset into the dmabuf where the payload starts. 'frag_offset'. 2. the size of the frag. 'frag_size'. 3. an opaque token 'frag_token' to return to the kernel when the buffer is to be released. The pages awaiting freeing are stored in the newly added sk->sk_user_frags, and each page passed to userspace is get_page()'d. This reference is dropped once the userspace indicates that it is done reading this page. All pages are released when the socket is destroyed. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20240910171458.219195-10-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-12net: netdev netlink api to bind dma-buf to a net deviceMina Almasry1-0/+11
API takes the dma-buf fd as input, and binds it to the netdevice. The user can specify the rx queues to bind the dma-buf to. Suggested-by: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Donald Hunter <donald.hunter@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-3-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-11net-timestamp: introduce SOF_TIMESTAMPING_OPT_RX_FILTER flagJason Xing1-1/+2
introduce a new flag SOF_TIMESTAMPING_OPT_RX_FILTER in the receive path. User can set it with SOF_TIMESTAMPING_SOFTWARE to filter out rx software timestamp report, especially after a process turns on netstamp_needed_key which can time stamp every incoming skb. Previously, we found out if an application starts first which turns on netstamp_needed_key, then another one only passing SOF_TIMESTAMPING_SOFTWARE could also get rx timestamp. Now we handle this case by introducing this new flag without breaking users. Quoting Willem to explain why we need the flag: "why a process would want to request software timestamp reporting, but not receive software timestamp generation. The only use I see is when the application does request SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_TX_SOFTWARE." Similarly, this new flag could also be used for hardware case where we can set it with SOF_TIMESTAMPING_RAW_HARDWARE, then we won't receive hardware receive timestamp. Another thing about errqueue in this patch I have a few words to say: In this case, we need to handle the egress path carefully, or else reporting the tx timestamp will fail. Egress path and ingress path will finally call sock_recv_timestamp(). We have to distinguish them. Errqueue is a good indicator to reflect the flow direction. Suggested-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20240909015612.3856-2-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-08ptp/ioctl: support MONOTONIC{,_RAW} timestamps for PTP_SYS_OFFSET_EXTENDEDMahesh Bandewar1-6/+18
The ability to read the PHC (Physical Hardware Clock) alongside multiple system clocks is currently dependent on the specific hardware architecture. This limitation restricts the use of PTP_SYS_OFFSET_PRECISE to certain hardware configurations. The generic soultion which would work across all architectures is to read the PHC along with the latency to perform PHC-read as offered by PTP_SYS_OFFSET_EXTENDED which provides pre and post timestamps. However, these timestamps are currently limited to the CLOCK_REALTIME timebase. Since CLOCK_REALTIME is affected by NTP (or similar time synchronization services), it can experience significant jumps forward or backward. This hinders the precise latency measurements that PTP_SYS_OFFSET_EXTENDED is designed to provide. This problem could be addressed by supporting MONOTONIC_RAW timestamps within PTP_SYS_OFFSET_EXTENDED. Unlike CLOCK_REALTIME or CLOCK_MONOTONIC, the MONOTONIC_RAW timebase is unaffected by NTP adjustments. This enhancement can be implemented by utilizing one of the three reserved words within the PTP_SYS_OFFSET_EXTENDED struct to pass the clock-id for timestamps. The current behavior aligns with clock-id for CLOCK_REALTIME timebase (value of 0), ensuring backward compatibility of the UAPI. Signed-off-by: Mahesh Bandewar <maheshb@google.com> Signed-off-by: Vadim Fedorenko <vadfed@meta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-09-07Merge tag 'nf-next-24-09-06' of ↵Jakub Kicinski1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next Pablo Neira Ayuso says: ==================== Netfilter updates for net-next The following patchset contains Netfilter updates for net-next: Patch #1 adds ctnetlink support for kernel side filtering for deletions, from Changliang Wu. Patch #2 updates nft_counter support to Use u64_stats_t, from Sebastian Andrzej Siewior. Patch #3 uses kmemdup_array() in all xtables frontends, from Yan Zhen. Patch #4 is a oneliner to use ERR_CAST() in nf_conntrack instead opencoded casting, from Shen Lichuan. Patch #5 removes unused argument in nftables .validate interface, from Florian Westphal. Patch #6 is a oneliner to correct a typo in nftables kdoc, from Simon Horman. Patch #7 fixes missing kdoc in nftables, also from Simon. Patch #8 updates nftables to handle timeout less than CONFIG_HZ. Patch #9 rejects element expiration if timeout is zero, otherwise it is silently ignored. Patch #10 disallows element expiration larger than timeout. Patch #11 removes unnecessary READ_ONCE annotation while mutex is held. Patch #12 adds missing READ_ONCE/WRITE_ONCE annotation in dynset. Patch #13 annotates data-races around element expiration. Patch #14 allocates timeout and expiration in one single set element extension, they are tighly couple, no reason to keep them separated anymore. Patch #15 updates nftables to interpret zero timeout element as never times out. Note that it is already possible to declare sets with elements that never time out but this generalizes to all kind of set with timeouts. Patch #16 supports for element timeout and expiration updates. * tag 'nf-next-24-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next: netfilter: nf_tables: set element timeout update support netfilter: nf_tables: zero timeout means element never times out netfilter: nf_tables: consolidate timeout extension for elements netfilter: nf_tables: annotate data-races around element expiration netfilter: nft_dynset: annotate data-races around set timeout netfilter: nf_tables: remove annotation to access set timeout while holding lock netfilter: nf_tables: reject expiration higher than timeout netfilter: nf_tables: reject element expiration with no timeout netfilter: nf_tables: elements with timeout below CONFIG_HZ never expire netfilter: nf_tables: Add missing Kernel doc netfilter: nf_tables: Correct spelling in nf_tables.h netfilter: nf_tables: drop unused 3rd argument from validate callback ops netfilter: conntrack: Convert to use ERR_CAST() netfilter: Use kmemdup_array instead of kmemdup for multiple allocation netfilter: nft_counter: Use u64_stats_t for statistic. netfilter: ctnetlink: support CTA_FILTER for flush ==================== Link: https://patch.msgid.link/20240905232920.5481-1-pablo@netfilter.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-05ipv4: Fix user space build failure due to header changeIdo Schimmel1-2/+0
RT_TOS() from include/uapi/linux/in_route.h is defined using IPTOS_TOS_MASK from include/uapi/linux/ip.h. This is problematic for files such as include/net/ip_fib.h that want to use RT_TOS() as without including both header files kernel compilation fails: In file included from ./include/net/ip_fib.h:25, from ./include/net/route.h:27, from ./include/net/lwtunnel.h:9, from net/core/dst.c:24: ./include/net/ip_fib.h: In function ‘fib_dscp_masked_match’: ./include/uapi/linux/in_route.h:31:32: error: ‘IPTOS_TOS_MASK’ undeclared (first use in this function) 31 | #define RT_TOS(tos) ((tos)&IPTOS_TOS_MASK) | ^~~~~~~~~~~~~~ ./include/net/ip_fib.h:440:45: note: in expansion of macro ‘RT_TOS’ 440 | return dscp == inet_dsfield_to_dscp(RT_TOS(fl4->flowi4_tos)); Therefore, cited commit changed linux/in_route.h to include linux/ip.h. However, as reported by David, this breaks iproute2 compilation due overlapping definitions between linux/ip.h and /usr/include/netinet/ip.h: In file included from ../include/uapi/linux/in_route.h:5, from iproute.c:19: ../include/uapi/linux/ip.h:25:9: warning: "IPTOS_TOS" redefined 25 | #define IPTOS_TOS(tos) ((tos)&IPTOS_TOS_MASK) | ^~~~~~~~~ In file included from iproute.c:17: /usr/include/netinet/ip.h:222:9: note: this is the location of the previous definition 222 | #define IPTOS_TOS(tos) ((tos) & IPTOS_TOS_MASK) Fix by changing include/net/ip_fib.h to include linux/ip.h. Note that usage of RT_TOS() should not spread further in the kernel due to recent work in this area. Fixes: 1fa3314c14c6 ("ipv4: Centralize TOS matching") Reported-by: David Ahern <dsahern@kernel.org> Closes: https://lore.kernel.org/netdev/2f5146ff-507d-4cab-a195-b28c0c9e654e@kernel.org/ Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Guillaume Nault <gnault@redhat.com> Link: https://patch.msgid.link/20240903133554.2807343-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-03netfilter: nf_tables: zero timeout means element never times outPablo Neira Ayuso1-1/+1
This patch uses zero as timeout marker for those elements that never expire when the element is created. If userspace provides no timeout for an element, then the default set timeout applies. However, if no default set timeout is specified and timeout flag is set on, then timeout extension is allocated and timeout is set to zero to allow for future updates. Use of zero a never timeout marker has been suggested by Phil Sutter. Note that, in older kernels, it is already possible to define elements that never expire by declaring a set with the set timeout flag set on and no global set timeout, in this case, new element with no explicit timeout never expire do not allocate the timeout extension, hence, they never expire. This approach makes it complicated to accomodate element timeout update, because element extensions do not support reallocations. Therefore, allocate the timeout extension and use the new marker for this case, but do not expose it to userspace to retain backward compatibility in the set listing. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2024-08-27dpll: add Embedded SYNC feature for a pinArkadiusz Kubalewski1-0/+3
Implement and document new pin attributes for providing Embedded SYNC capabilities to the DPLL subsystem users through a netlink pin-get do/dump messages. Allow the user to set Embedded SYNC frequency with pin-set do netlink message. Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com> Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://patch.msgid.link/20240822222513.255179-2-arkadiusz.kubalewski@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26net: Correct spelling in headersSimon Horman2-2/+2
Correct spelling in Networking headers. As reported by codespell. Signed-off-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20240822-net-spell-v1-12-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26packet: Correct spelling in if_packet.hSimon Horman1-3/+4
Correct spelling in if_packet.h As reported by codespell. Signed-off-by: Simon Horman <horms@kernel.org> Acked-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20240822-net-spell-v1-1-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26ethtool: Extend cable testing interface with result source informationOleksij Rempel1-0/+11
Extend the ethtool netlink cable testing interface by adding support for specifying the source of cable testing results. This allows users to differentiate between results obtained through different diagnostic methods. For example, some TI 10BaseT1L PHYs provide two variants of cable diagnostics: Time Domain Reflectometry (TDR) and Active Link Cable Diagnostic (ALCD). By introducing `ETHTOOL_A_CABLE_RESULT_SRC` and `ETHTOOL_A_CABLE_FAULT_LENGTH_SRC` attributes, this update enables drivers to indicate whether the result was derived from TDR or ALCD, improving the clarity and utility of diagnostic information. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/20240822120703.1393130-2-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26Merge tag 'for-netdev' of ↵Jakub Kicinski1-1/+2
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Daniel Borkmann says: ==================== pull-request: bpf-next 2024-08-23 We've added 10 non-merge commits during the last 15 day(s) which contain a total of 10 files changed, 222 insertions(+), 190 deletions(-). The main changes are: 1) Add TCP_BPF_SOCK_OPS_CB_FLAGS to bpf_*sockopt() to address the case when long-lived sockets miss a chance to set additional callbacks if a sockops program was not attached early in their lifetime, from Alan Maguire. 2) Add a batch of BPF selftest improvements which fix a few bugs and add missing features to improve the test coverage of sockmap/sockhash, from Michal Luczaj. 3) Fix a false-positive Smatch-reported off-by-one in tcp_validate_cookie() which is part of the test_tcp_custom_syncookie BPF selftest, from Kuniyuki Iwashima. 4) Fix the flow_dissector BPF selftest which had a bug in IP header's tot_len calculation doing subtraction after htons() instead of inside htons(), from Asbjørn Sloth Tønnesen. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: selftest: bpf: Remove mssind boundary check in test_tcp_custom_syncookie.c. selftests/bpf: Introduce __attribute__((cleanup)) in create_pair() selftests/bpf: Exercise SOCK_STREAM unix_inet_redir_to_connected() selftests/bpf: Honour the sotype of af_unix redir tests selftests/bpf: Simplify inet_socketpair() and vsock_socketpair_connectible() selftests/bpf: Socket pair creation, cleanups selftests/bpf: Support more socket types in create_pair() selftests/bpf: Avoid subtraction after htons() in ipip tests selftests/bpf: add sockopt tests for TCP_BPF_SOCK_OPS_CB_FLAGS bpf/bpf_get,set_sockopt: add option to set TCP-BPF sock ops flags ==================== Link: https://patch.msgid.link/20240823134959.1091-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-23net: ethtool: Introduce a command to list PHYs on an interfaceMaxime Chevallier1-0/+19
As we have the ability to track the PHYs connected to a net_device through the link_topology, we can expose this list to userspace. This allows userspace to use these identifiers for phy-specific commands and take the decision of which PHY to target by knowing the link topology. Add PHY_GET and PHY_DUMP, which can be a filtered DUMP operation to list devices on only one interface. Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-23net: ethtool: Allow passing a phy index for some commandsMaxime Chevallier1-0/+1
Some netlink commands are target towards ethernet PHYs, to control some of their features. As there's several such commands, add the ability to pass a PHY index in the ethnl request, which will populate the generic ethnl_req_info with the passed phy_index. Add a helper that netlink command handlers need to use to grab the targeted PHY from the req_info. This helper needs to hold rtnl_lock() while interacting with the PHY, as it may be removed at any point. Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-23net: phy: Introduce ethernet link topology representationMaxime Chevallier1-0/+16
Link topologies containing multiple network PHYs attached to the same net_device can be found when using a PHY as a media converter for use with an SFP connector, on which an SFP transceiver containing a PHY can be used. With the current model, the transceiver's PHY can't be used for operations such as cable testing, timestamping, macsec offload, etc. The reason being that most of the logic for these configuration, coming from either ethtool netlink or ioctls tend to use netdev->phydev, which in multi-phy systems will reference the PHY closest to the MAC. Introduce a numbering scheme allowing to enumerate PHY devices that belong to any netdev, which can in turn allow userspace to take more precise decisions with regard to each PHY's configuration. The numbering is maintained per-netdev, in a phy_device_list. The numbering works similarly to a netdevice's ifindex, with identifiers that are only recycled once INT_MAX has been reached. This prevents races that could occur between PHY listing and SFP transceiver removal/insertion. The identifiers are assigned at phy_attach time, as the numbering depends on the netdevice the phy is attached to. The PHY index can be re-used for PHYs that are persistent. Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+1
Cross-merge networking fixes after downstream PR. No conflicts. Adjacent changes: drivers/net/ethernet/broadcom/bnxt/bnxt.h c948c0973df5 ("bnxt_en: Don't clear ntuple filters and rss contexts during ethtool ops") f2878cdeb754 ("bnxt_en: Add support to call FW to update a VNIC") Link: https://patch.msgid.link/20240822210125.1542769-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-22net: ipv6: ioam6: new feature tunsrcJustin Iurman1-0/+6
This patch provides a new feature (i.e., "tunsrc") for the tunnel (i.e., "encap") mode of ioam6. Just like seg6 already does, except it is attached to a route. The "tunsrc" is optional: when not provided (by default), the automatic resolution is applied. Using "tunsrc" when possible has a benefit: performance. See the comparison: - before (= "encap" mode): https://ibb.co/bNCzvf7 - after (= "encap" mode with "tunsrc"): https://ibb.co/PT8L6yq Signed-off-by: Justin Iurman <justin.iurman@uliege.be> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-08-20ipv4: Centralize TOS matchingIdo Schimmel1-0/+2
The TOS field in the IPv4 flow information structure ('flowi4_tos') is matched by the kernel against the TOS selector in IPv4 rules and routes. The field is initialized differently by different call sites. Some treat it as DSCP (RFC 2474) and initialize all six DSCP bits, some treat it as RFC 1349 TOS and initialize it using RT_TOS() and some treat it as RFC 791 TOS and initialize it using IPTOS_RT_MASK. What is common to all these call sites is that they all initialize the lower three DSCP bits, which fits the TOS definition in the initial IPv4 specification (RFC 791). Therefore, the kernel only allows configuring IPv4 FIB rules that match on the lower three DSCP bits which are always guaranteed to be initialized by all call sites: # ip -4 rule add tos 0x1c table 100 # ip -4 rule add tos 0x3c table 100 Error: Invalid tos. While this works, it is unlikely to be very useful. RFC 791 that initially defined the TOS and IP precedence fields was updated by RFC 2474 over twenty five years ago where these fields were replaced by a single six bits DSCP field. Extending FIB rules to match on DSCP can be done by adding a new DSCP selector while maintaining the existing semantics of the TOS selector for applications that rely on that. A prerequisite for allowing FIB rules to match on DSCP is to adjust all the call sites to initialize the high order DSCP bits and remove their masking along the path to the core where the field is matched on. However, making this change alone will result in a behavior change. For example, a forwarded IPv4 packet with a DS field of 0xfc will no longer match a FIB rule that was configured with 'tos 0x1c'. This behavior change can be avoided by masking the upper three DSCP bits in 'flowi4_tos' before comparing it against the TOS selectors in FIB rules and routes. Implement the above by adding a new function that checks whether a given DSCP value matches the one specified in the IPv4 flow information structure and invoke it from the three places that currently match on 'flowi4_tos'. Use RT_TOS() for the masking of 'flowi4_tos' instead of IPTOS_RT_MASK since the latter is not uAPI and we should be able to remove it at some point. Include <linux/ip.h> in <linux/in_route.h> since the former defines IPTOS_TOS_MASK which is used in the definition of RT_TOS() in <linux/in_route.h>. No regressions in FIB tests: # ./fib_tests.sh [...] Tests passed: 218 Tests failed: 0 And FIB rule tests: # ./fib_rule_tests.sh [...] Tests passed: 116 Tests failed: 0 Signed-off-by: Ido Schimmel <idosch@nvidia.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-08-20net/smc: introduce statistics for ringbufs usage of net namespaceWen Gu1-0/+2
The buffer size histograms in smc_stats, namely rx/tx_rmbsize, record the sizes of ringbufs for all connections that have ever appeared in the net namespace. They are incremental and we cannot know the actual ringbufs usage from these. So here introduces statistics for current ringbufs usage of existing smc connections in the net namespace into smc_stats, it will be incremented when new connection uses a ringbuf and decremented when the ringbuf is unused. Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-08-20net/smc: introduce statistics for allocated ringbufs of link groupWen Gu1-0/+4
Currently we have the statistics on sndbuf/RMB sizes of all connections that have ever been on the link group, namely smc_stats_memsize. However these statistics are incremental and since the ringbufs of link group are allowed to be reused, we cannot know the actual allocated buffers through these. So here introduces the statistic on actual allocated ringbufs of the link group, it will be incremented when a new ringbuf is added into buf_list and decremented when it is deleted from buf_list. Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-08-17Merge tag 'io_uring-6.11-20240824' of git://git.kernel.dk/linuxLinus Torvalds1-1/+1
Pull io_uring fixes from Jens Axboe: - Fix a comment in the uapi header using the wrong member name (Caleb) - Fix KCSAN warning for a debug check in sqpoll (me) - Two more NAPI tweaks (Olivier) * tag 'io_uring-6.11-20240824' of git://git.kernel.dk/linux: io_uring: fix user_data field name in comment io_uring/sqpoll: annotate debug task == current with data_race() io_uring/napi: remove duplicate io_napi_entry timeout assignation io_uring/napi: check napi_enabled in io_napi_add() before proceeding
2024-08-16io_uring: fix user_data field name in commentCaleb Sander Mateos1-1/+1
io_uring_cqe's user_data field refers to `sqe->data`, but io_uring_sqe does not have a data field. Fix the comment to say `sqe->user_data`. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Link: https://github.com/axboe/liburing/pull/1206 Link: https://lore.kernel.org/r/20240816181526.3642732-1-csander@purestorage.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-08-16ethtool: Add new result codes for TDR diagnosticsOleksij Rempel1-0/+4
Add new result codes to support TDR diagnostics in preparation for Open Alliance 1000BaseT1 TDR support: - ETHTOOL_A_CABLE_RESULT_CODE_NOISE: TDR not possible due to high noise level. - ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE: TDR resolution not possible / out of distance. Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Link: https://patch.msgid.link/20240812073046.1728288-1-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski2-1/+3
Cross-merge networking fixes after downstream PR. Conflicts: Documentation/devicetree/bindings/net/fsl,qoriq-mc-dpmac.yaml c25504a0ba36 ("dt-bindings: net: fsl,qoriq-mc-dpmac: add missed property phys") be034ee6c33d ("dt-bindings: net: fsl,qoriq-mc-dpmac: using unevaluatedProperties") https://lore.kernel.org/20240815110934.56ae623a@canb.auug.org.au drivers/net/dsa/vitesse-vsc73xx-core.c 5b9eebc2c7a5 ("net: dsa: vsc73xx: pass value in phy_write operation") fa63c6434b6f ("net: dsa: vsc73xx: check busy flag in MDIO operations") 2524d6c28bdc ("net: dsa: vsc73xx: use defined values in phy operations") https://lore.kernel.org/20240813104039.429b9fe6@canb.auug.org.au Resolve by using FIELD_PREP(), Stephen's resolution is simpler. Adjacent changes: net/vmw_vsock/af_vsock.c 69139d2919dd ("vsock: fix recursive ->recvmsg calls") 744500d81f81 ("vsock: add support for SIOCOUTQ ioctl") Link: https://patch.msgid.link/20240815141149.33862-1-pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-15UAPI: net/sched: Use __struct_group() in flex struct tc_u32_selGustavo A. R. Silva1-10/+13
Use the `__struct_group()` helper to create a new tagged `struct tc_u32_sel_hdr`. This structure groups together all the members of the flexible `struct tc_u32_sel` except the flexible array. As a result, the array is effectively separated from the rest of the members without modifying the memory layout of the flexible structure. This new tagged struct will be used to fix problematic declarations of middle-flex-arrays in composite structs[1]. [1] https://git.kernel.org/linus/d88cabfd9abc Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://patch.msgid.link/e59fe833564ddc5b2cc83056a4c504be887d6193.1723586870.git.gustavoars@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-14Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+1
Pull kvm fixes from Paolo Bonzini: "s390: - Fix failure to start guests with kvm.use_gisa=0 - Panic if (un)share fails to maintain security. ARM: - Use kvfree() for the kvmalloc'd nested MMUs array - Set of fixes to address warnings in W=1 builds - Make KVM depend on assembler support for ARMv8.4 - Fix for vgic-debug interface for VMs without LPIs - Actually check ID_AA64MMFR3_EL1.S1PIE in get-reg-list selftest - Minor code / comment cleanups for configuring PAuth traps - Take kvm->arch.config_lock to prevent destruction / initialization race for a vCPU's CPUIF which may lead to a UAF x86: - Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) - Fix smatch issues - Small cleanups - Make x2APIC ID 100% readonly - Fix typo in uapi constant Generic: - Use synchronize_srcu_expedited() on irqfd shutdown" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits) KVM: SEV: uapi: fix typo in SEV_RET_INVALID_CONFIG KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) KVM: eventfd: Use synchronize_srcu_expedited() on shutdown KVM: selftests: Add a testcase to verify x2APIC is fully readonly KVM: x86: Make x2APIC ID 100% readonly KVM: x86: Use this_cpu_ptr() instead of per_cpu_ptr(smp_processor_id()) KVM: x86: hyper-v: Remove unused inline function kvm_hv_free_pa_page() KVM: SVM: Fix an error code in sev_gmem_post_populate() KVM: SVM: Fix uninitialized variable bug KVM: arm64: vgic: Hold config_lock while tearing down a CPU interface KVM: selftests: arm64: Correct feature test for S1PIE in get-reg-list KVM: arm64: Tidying up PAuth code in KVM KVM: arm64: vgic-debug: Exit the iterator properly w/o LPI KVM: arm64: Enforce dependency on an ARMv8.4-aware toolchain s390/uv: Panic for set and remove shared access UVC errors KVM: s390: fix validity interception issue when gisa is switched off docs: KVM: Fix register ID of SPSR_FIQ KVM: arm64: vgic: fix unexpected unlock sparse warnings KVM: arm64: fix kdoc warnings in W=1 builds KVM: arm64: fix override-init warnings in W=1 builds ...
2024-08-14KVM: SEV: uapi: fix typo in SEV_RET_INVALID_CONFIGAmit Shah1-0/+1
"INVALID" is misspelt in "SEV_RET_INAVLID_CONFIG". Since this is part of the UAPI, keep the current definition and add a new one with the fix. Fix-suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Amit Shah <amit.shah@amd.com> Message-ID: <20240814083113.21622-1-amit@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-08-13net: nexthop: Increase weight to u16Petr Machata1-1/+6
In CLOS networks, as link failures occur at various points in the network, ECMP weights of the involved nodes are adjusted to compensate. With high fan-out of the involved nodes, and overall high number of nodes, a (non-)ECMP weight ratio that we would like to configure does not fit into 8 bits. Instead of, say, 255:254, we might like to configure something like 1000:999. For these deployments, the 8-bit weight may not be enough. To that end, in this patch increase the next hop weight from u8 to u16. Increasing the width of an integral type can be tricky, because while the code still compiles, the types may not check out anymore, and numerical errors come up. To prevent this, the conversion was done in two steps. First the type was changed from u8 to a single-member structure, which invalidated all uses of the field. This allowed going through them one by one and audit for type correctness. Then the structure was replaced with a vanilla u16 again. This should ensure that no place was missed. The UAPI for configuring nexthop group members is that an attribute NHA_GROUP carries an array of struct nexthop_grp entries: struct nexthop_grp { __u32 id; /* nexthop id - must exist */ __u8 weight; /* weight of this nexthop */ __u8 resvd1; __u16 resvd2; }; The field resvd1 is currently validated and required to be zero. We can lift this requirement and carry high-order bits of the weight in the reserved field: struct nexthop_grp { __u32 id; /* nexthop id - must exist */ __u8 weight; /* weight of this nexthop */ __u8 weight_high; __u16 resvd2; }; Keeping the fields split this way was chosen in case an existing userspace makes assumptions about the width of the weight field, and to sidestep any endianness issues. The weight field is currently encoded as the weight value minus one, because weight of 0 is invalid. This same trick is impossible for the new weight_high field, because zero must mean actual zero. With this in place: - Old userspace is guaranteed to carry weight_high of 0, therefore configuring 8-bit weights as appropriate. When dumping nexthops with 16-bit weight, it would only show the lower 8 bits. But configuring such nexthops implies existence of userspace aware of the extension in the first place. - New userspace talking to an old kernel will work as long as it only attempts to configure 8-bit weights, where the high-order bits are zero. Old kernel will bounce attempts at configuring >8-bit weights. Renaming reserved fields as they are allocated for some purpose is commonly done in Linux. Whoever touches a reserved field is doing so at their own risk. nexthop_grp::resvd1 in particular is currently used by at least strace, however they carry an own copy of UAPI headers, and the conversion should be trivial. A helper is provided for decoding the weight out of the two fields. Forcing a conversion seems preferable to bending backwards and introducing anonymous unions or whatever. Signed-off-by: Petr Machata <petrm@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Link: https://patch.msgid.link/483e2fcf4beb0d9135d62e7d27b46fa2685479d4.1723036486.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-13net: nexthop: Add flag to assert that NHGRP reserved fields are zeroPetr Machata1-0/+3
There are many unpatched kernel versions out there that do not initialize the reserved fields of struct nexthop_grp. The issue with that is that if those fields were to be used for some end (i.e. stop being reserved), old kernels would still keep sending random data through the field, and a new userspace could not rely on the value. In this patch, use the existing NHA_OP_FLAGS, which is currently inbound only, to carry flags back to the userspace. Add a flag to indicate that the reserved fields in struct nexthop_grp are zeroed before dumping. This is reliant on the actual fix from commit 6d745cd0e972 ("net: nexthop: Initialize all fields in dumped nexthops"). Signed-off-by: Petr Machata <petrm@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/21037748d4f9d8ff486151f4c09083bcf12d5df8.1723036486.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-12nsfs: fix ioctl declarationChristian Brauner1-1/+2
The kernel is writing an object of type __u64, so the ioctl has to be defined to _IOR(NSIO, 0x5, __u64) instead of _IO(NSIO, 0x5). Reported-by: Dmitry V. Levin <ldv@strace.io> Link: https://lore.kernel.org/r/20240730164554.GA18486@altlinux.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-12ethtool: rss: support skipping contexts during dumpJakub Kicinski1-0/+1
Applications may want to deal with dynamic RSS contexts only. So dumping context 0 will be counter-productive for them. Support starting the dump from a given context ID. Alternative would be to implement a dump flag to skip just context 0, not sure which is better... Reviewed-by: Edward Cree <ecree.xilinx@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-09bpf/bpf_get,set_sockopt: add option to set TCP-BPF sock ops flagsAlan Maguire1-1/+2
Currently the only opportunity to set sock ops flags dictating which callbacks fire for a socket is from within a TCP-BPF sockops program. This is problematic if the connection is already set up as there is no further chance to specify callbacks for that socket. Add TCP_BPF_SOCK_OPS_CB_FLAGS to bpf_setsockopt() and bpf_getsockopt() to allow users to specify callbacks later, either via an iterator over sockets or via a socket-specific program triggered by a setsockopt() on the socket. Previous discussion on this here [1]. [1] https://lore.kernel.org/bpf/f42f157b-6e52-dd4d-3d97-9b86c84c0b00@oracle.com/ Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/r/20240808150558.1035626-2-alan.maguire@oracle.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2024-07-25Merge tag 'net-6.11-rc1' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from bpf and netfilter. A lot of networking people were at a conference last week, busy catching COVID, so relatively short PR. Current release - regressions: - tcp: process the 3rd ACK with sk_socket for TFO and MPTCP Current release - new code bugs: - l2tp: protect session IDR and tunnel session list with one lock, make sure the state is coherent to avoid a warning - eth: bnxt_en: update xdp_rxq_info in queue restart logic - eth: airoha: fix location of the MBI_RX_AGE_SEL_MASK field Previous releases - regressions: - xsk: require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len, the field reuses previously un-validated pad Previous releases - always broken: - tap/tun: drop short frames to prevent crashes later in the stack - eth: ice: add a per-VF limit on number of FDIR filters - af_unix: disable MSG_OOB handling for sockets in sockmap/sockhash" * tag 'net-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (34 commits) tun: add missing verification for short frame tap: add missing verification for short frame mISDN: Fix a use after free in hfcmulti_tx() gve: Fix an edge case for TSO skb validity check bnxt_en: update xdp_rxq_info in queue restart logic tcp: process the 3rd ACK with sk_socket for TFO/MPTCP selftests/bpf: Add XDP_UMEM_TX_METADATA_LEN to XSK TX metadata test xsk: Require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len bpf: Fix a segment issue when downgrading gso_size net: mediatek: Fix potential NULL pointer dereference in dummy net_device handling MAINTAINERS: make Breno the netconsole maintainer MAINTAINERS: Update bonding entry net: nexthop: Initialize all fields in dumped nexthops net: stmmac: Correct byte order of perfect_match selftests: forwarding: skip if kernel not support setting bridge fdb learning limit tipc: Return non-zero value from tipc_udp_addr2str() on error netfilter: nft_set_pipapo_avx2: disable softinterrupts ice: Fix recipe read procedure ice: Add a per-VF limit on number of FDIR filters net: bonding: correctly annotate RCU in bond_should_notify_peers() ...
2024-07-25Merge tag 'uml-for-linus-6.11-rc1' of ↵Linus Torvalds1-14/+176
git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux Pull UML updates from Richard Weinberger: - Support for preemption - i386 Rust support - Huge cleanup by Benjamin Berg - UBSAN support - Removal of dead code * tag 'uml-for-linus-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (41 commits) um: vector: always reset vp->opened um: vector: remove vp->lock um: register power-off handler um: line: always fill *error_out in setup_one_line() um: remove pcap driver from documentation um: Enable preemption in UML um: refactor TLB update handling um: simplify and consolidate TLB updates um: remove force_flush_all from fork_handler um: Do not flush MM in flush_thread um: Delay flushing syscalls until the thread is restarted um: remove copy_context_skas0 um: remove LDT support um: compress memory related stub syscalls while adding them um: Rework syscall handling um: Add generic stub_syscall6 function um: Create signal stack memory assignment in stub_data um: Remove stub-data.h include from common-offsets.h um: time-travel: fix signal blocking race/hang um: time-travel: remove time_exit() ...
2024-07-25Merge tag 'for-netdev' of ↵Jakub Kicinski1-0/+4
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf Daniel Borkmann says: ==================== pull-request: bpf 2024-07-25 We've added 14 non-merge commits during the last 8 day(s) which contain a total of 19 files changed, 177 insertions(+), 70 deletions(-). The main changes are: 1) Fix af_unix to disable MSG_OOB handling for sockets in BPF sockmap and BPF sockhash. Also add test coverage for this case, from Michal Luczaj. 2) Fix a segmentation issue when downgrading gso_size in the BPF helper bpf_skb_adjust_room(), from Fred Li. 3) Fix a compiler warning in resolve_btfids due to a missing type cast, from Liwei Song. 4) Fix stack allocation for arm64 to align the stack pointer at a 16 byte boundary in the fexit_sleep BPF selftest, from Puranjay Mohan. 5) Fix a xsk regression to require a flag when actuating tx_metadata_len, from Stanislav Fomichev. 6) Fix function prototype BTF dumping in libbpf for prototypes that have no input arguments, from Andrii Nakryiko. 7) Fix stacktrace symbol resolution in perf script for BPF programs containing subprograms, from Hou Tao. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: selftests/bpf: Add XDP_UMEM_TX_METADATA_LEN to XSK TX metadata test xsk: Require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len bpf: Fix a segment issue when downgrading gso_size tools/resolve_btfids: Fix comparison of distinct pointer types warning in resolve_btfids bpf, events: Use prog to emit ksymbol event for main program selftests/bpf: Test sockmap redirect for AF_UNIX MSG_OOB selftests/bpf: Parametrize AF_UNIX redir functions to accept send() flags selftests/bpf: Support SOCK_STREAM in unix_inet_redir_to_connected() af_unix: Disable MSG_OOB handling for sockets in sockmap/sockhash bpftool: Fix typo in usage help libbpf: Fix no-args func prototype BTF dumping syntax MAINTAINERS: Update powerpc BPF JIT maintainers MAINTAINERS: Update email address of Naveen selftests/bpf: fexit_sleep: Fix stack allocation for arm64 ==================== Link: https://patch.msgid.link/20240725114312.32197-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-07-25xsk: Require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_lenStanislav Fomichev1-0/+4
Julian reports that commit 341ac980eab9 ("xsk: Support tx_metadata_len") can break existing use cases which don't zero-initialize xdp_umem_reg padding. Introduce new XDP_UMEM_TX_METADATA_LEN to make sure we interpret the padding as tx_metadata_len only when being explicitly asked. Fixes: 341ac980eab9 ("xsk: Support tx_metadata_len") Reported-by: Julian Schindel <mail@arctic-alpaca.de> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20240713015253.121248-2-sdf@fomichev.me
2024-07-24Merge tag 'random-6.11-rc1-for-linus' of ↵Linus Torvalds2-1/+17
git://git.kernel.org/pub/scm/linux/kernel/git/crng/random Pull random number generator updates from Jason Donenfeld: "This adds getrandom() support to the vDSO. First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which lets the kernel zero out pages anytime under memory pressure, which enables allocating memory that never gets swapped to disk but also doesn't count as being mlocked. Then, the vDSO implementation of getrandom() is introduced in a generic manner and hooked into random.c. Next, this is implemented on x86. (Also, though it's not ready for this pull, somebody has begun an arm64 implementation already) Finally, two vDSO selftests are added. There are also two housekeeping cleanup commits" * tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: MAINTAINERS: add random.h headers to RNG subsection random: note that RNDGETPOOL was removed in 2.6.9-rc2 selftests/vDSO: add tests for vgetrandom x86: vdso: Wire up getrandom() vDSO implementation random: introduce generic vDSO getrandom() implementation mm: add MAP_DROPPABLE for designating always lazily freeable mappings
2024-07-22Merge tag 'mm-stable-2024-07-21-14-50' of ↵Linus Torvalds1-1/+157
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - In the series "mm: Avoid possible overflows in dirty throttling" Jan Kara addresses a couple of issues in the writeback throttling code. These fixes are also targetted at -stable kernels. - Ryusuke Konishi's series "nilfs2: fix potential issues related to reserved inodes" does that. This should actually be in the mm-nonmm-stable tree, along with the many other nilfs2 patches. My bad. - More folio conversions from Kefeng Wang in the series "mm: convert to folio_alloc_mpol()" - Kemeng Shi has sent some cleanups to the writeback code in the series "Add helper functions to remove repeated code and improve readability of cgroup writeback" - Kairui Song has made the swap code a little smaller and a little faster in the series "mm/swap: clean up and optimize swap cache index". - In the series "mm/memory: cleanly support zeropage in vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David Hildenbrand has reworked the rather sketchy handling of the use of the zeropage in MAP_SHARED mappings. I don't see any runtime effects here - more a cleanup/understandability/maintainablity thing. - Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling of higher addresses, for aarch64. The (poorly named) series is "Restructure va_high_addr_switch". - The core TLB handling code gets some cleanups and possible slight optimizations in Bang Li's series "Add update_mmu_tlb_range() to simplify code". - Jane Chu has improved the handling of our fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in the series "Enhance soft hwpoison handling and injection". - Jeff Johnson has sent a billion patches everywhere to add MODULE_DESCRIPTION() to everything. Some landed in this pull. - In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang has simplified migration's use of hardware-offload memory copying. - Yosry Ahmed performs more folio API conversions in his series "mm: zswap: trivial folio conversions". - In the series "large folios swap-in: handle refault cases first", Chuanhua Han inches us forward in the handling of large pages in the swap code. This is a cleanup and optimization, working toward the end objective of full support of large folio swapin/out. - In the series "mm,swap: cleanup VMA based swap readahead window calculation", Huang Ying has contributed some cleanups and a possible fixlet to his VMA based swap readahead code. - In the series "add mTHP support for anonymous shmem" Baolin Wang has taught anonymous shmem mappings to use multisize THP. By default this is a no-op - users must opt in vis sysfs controls. Dramatic improvements in pagefault latency are realized. - David Hildenbrand has some cleanups to our remaining use of page_mapcount() in the series "fs/proc: move page_mapcount() to fs/proc/internal.h". - David also has some highmem accounting cleanups in the series "mm/highmem: don't track highmem pages manually". - Build-time fixes and cleanups from John Hubbard in the series "cleanups, fixes, and progress towards avoiding "make headers"". - Cleanups and consolidation of the core pagemap handling from Barry Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers and utilize them". - Lance Yang's series "Reclaim lazyfree THP without splitting" has reduced the latency of the reclaim of pmd-mapped THPs under fairly common circumstances. A 10x speedup is seen in a microbenchmark. It does this by punting to aother CPU but I guess that's a win unless all CPUs are pegged. - hugetlb_cgroup cleanups from Xiu Jianfeng in the series "mm/hugetlb_cgroup: rework on cftypes". - Miaohe Lin's series "Some cleanups for memory-failure" does just that thing. - Someone other than SeongJae has developed a DAMON feature in Honggyu Kim's series "DAMON based tiered memory management for CXL memory". This adds DAMON features which may be used to help determine the efficiency of our placement of CXL/PCIe attached DRAM. - DAMON user API centralization and simplificatio work in SeongJae Park's series "mm/damon: introduce DAMON parameters online commit function". - In the series "mm: page_type, zsmalloc and page_mapcount_reset()" David Hildenbrand does some maintenance work on zsmalloc - partially modernizing its use of pageframe fields. - Kefeng Wang provides more folio conversions in the series "mm: remove page_maybe_dma_pinned() and page_mkclean()". - More cleanup from David Hildenbrand, this time in the series "mm/memory_hotplug: use PageOffline() instead of PageReserved() for !ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline() pages" and permits the removal of some virtio-mem hacks. - Barry Song's series "mm: clarify folio_add_new_anon_rmap() and __folio_add_anon_rmap()" is a cleanup to the anon folio handling in preparation for mTHP (multisize THP) swapin. - Kefeng Wang's series "mm: improve clear and copy user folio" implements more folio conversions, this time in the area of large folio userspace copying. - The series "Docs/mm/damon/maintaier-profile: document a mailing tool and community meetup series" tells people how to get better involved with other DAMON developers. From SeongJae Park. - A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does that. - David Hildenbrand sends along more cleanups, this time against the migration code. The series is "mm/migrate: move NUMA hinting fault folio isolation + checks under PTL". - Jan Kara has found quite a lot of strangenesses and minor errors in the readahead code. He addresses this in the series "mm: Fix various readahead quirks". - SeongJae Park's series "selftests/damon: test DAMOS tried regions and {min,max}_nr_regions" adds features and addresses errors in DAMON's self testing code. - Gavin Shan has found a userspace-triggerable WARN in the pagecache code. The series "mm/filemap: Limit page cache size to that supported by xarray" addresses this. The series is marked cc:stable. - Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations and cleanup" cleans up and slightly optimizes KSM. - Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of code motion. The series (which also makes the memcg-v1 code Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put under config option" and "mm: memcg: put cgroup v1-specific memcg data under CONFIG_MEMCG_V1" - Dan Schatzberg's series "Add swappiness argument to memory.reclaim" adds an additional feature to this cgroup-v2 control file. - The series "Userspace controls soft-offline pages" from Jiaqi Yan permits userspace to stop the kernel's automatic treatment of excessive correctable memory errors. In order to permit userspace to monitor and handle this situation. - Kefeng Wang's series "mm: migrate: support poison recover from migrate folio" teaches the kernel to appropriately handle migration from poisoned source folios rather than simply panicing. - SeongJae Park's series "Docs/damon: minor fixups and improvements" does those things. - In the series "mm/zsmalloc: change back to per-size_class lock" Chengming Zhou improves zsmalloc's scalability and memory utilization. - Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for pinning memfd folios" makes the GUP code use FOLL_PIN rather than bare refcount increments. So these paes can first be moved aside if they reside in the movable zone or a CMA block. - Andrii Nakryiko has added a binary ioctl()-based API to /proc/pid/maps for much faster reading of vma information. The series is "query VMAs from /proc/<pid>/maps". - In the series "mm: introduce per-order mTHP split counters" Lance Yang improves the kernel's presentation of developer information related to multisize THP splitting. - Michael Ellerman has developed the series "Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64)". This permits userspace to use all available huge page sizes. - In the series "revert unconditional slab and page allocator fault injection calls" Vlastimil Babka removes a performance-affecting and not very useful feature from slab fault injection. * tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits) mm/mglru: fix ineffective protection calculation mm/zswap: fix a white space issue mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio mm/hugetlb: fix possible recursive locking detected warning mm/gup: clear the LRU flag of a page before adding to LRU batch mm/numa_balancing: teach mpol_to_str about the balancing mode mm: memcg1: convert charge move flags to unsigned long long alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting lib: reuse page_ext_data() to obtain codetag_ref lib: add missing newline character in the warning message mm/mglru: fix overshooting shrinker memory mm/mglru: fix div-by-zero in vmpressure_calc_level() mm/kmemleak: replace strncpy() with strscpy() mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB mm: ignore data-race in __swap_writepage hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr mm: shmem: rename mTHP shmem counters mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async() mm/migrate: putback split folios when numa hint migration fails ...
2024-07-20Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds3-1/+56
Pull kvm updates from Paolo Bonzini: "ARM: - Initial infrastructure for shadow stage-2 MMUs, as part of nested virtualization enablement - Support for userspace changes to the guest CTR_EL0 value, enabling (in part) migration of VMs between heterogenous hardware - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of the protocol - FPSIMD/SVE support for nested, including merged trap configuration and exception routing - New command-line parameter to control the WFx trap behavior under KVM - Introduce kCFI hardening in the EL2 hypervisor - Fixes + cleanups for handling presence/absence of FEAT_TCRX - Miscellaneous fixes + documentation updates LoongArch: - Add paravirt steal time support - Add support for KVM_DIRTY_LOG_INITIALLY_SET - Add perf kvm-stat support for loongarch RISC-V: - Redirect AMO load/store access fault traps to guest - perf kvm stat support - Use guest files for IMSIC virtualization, when available s390: - Assortment of tiny fixes which are not time critical x86: - Fixes for Xen emulation - Add a global struct to consolidate tracking of host values, e.g. EFER - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC bus frequency, because TDX - Print the name of the APICv/AVIC inhibits in the relevant tracepoint - Clean up KVM's handling of vendor specific emulation to consistently act on "compatible with Intel/AMD", versus checking for a specific vendor - Drop MTRR virtualization, and instead always honor guest PAT on CPUs that support self-snoop - Update to the newfangled Intel CPU FMS infrastructure - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads '0' and writes from userspace are ignored - Misc cleanups x86 - MMU: - Small cleanups, renames and refactoring extracted from the upcoming Intel TDX support - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't hold leafs SPTEs - Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager page splitting, to avoid stalling vCPUs when splitting huge pages - Bug the VM instead of simply warning if KVM tries to split a SPTE that is non-present or not-huge. KVM is guaranteed to end up in a broken state because the callers fully expect a valid SPTE, it's all but dangerous to let more MMU changes happen afterwards x86 - AMD: - Make per-CPU save_area allocations NUMA-aware - Force sev_es_host_save_area() to be inlined to avoid calling into an instrumentable function from noinstr code - Base support for running SEV-SNP guests. API-wise, this includes a new KVM_X86_SNP_VM type, encrypting/measure the initial image into guest memory, and finalizing it before launching it. Internally, there are some gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges This includes basic support for attestation guest requests, enough to say that KVM supports the GHCB 2.0 specification There is no support yet for loading into the firmware those signing keys to be used for attestation requests, and therefore no need yet for the host to provide certificate data for those keys. To support fetching certificate data from userspace, a new KVM exit type will be needed to handle fetching the certificate from userspace. An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS exit type to handle this was introduced in v1 of this patchset, but is still being discussed by community, so for now this patchset only implements a stub version of SNP Extended Guest Requests that does not provide certificate data x86 - Intel: - Remove an unnecessary EPT TLB flush when enabling hardware - Fix a series of bugs that cause KVM to fail to detect nested pending posted interrupts as valid wake eents for a vCPU executing HLT in L2 (with HLT-exiting disable by L1) - KVM: x86: Suppress MMIO that is triggered during task switch emulation Explicitly suppress userspace emulated MMIO exits that are triggered when emulating a task switch as KVM doesn't support userspace MMIO during complex (multi-step) emulation Silently ignoring the exit request can result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace for some other reason prior to purging mmio_needed See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write exits if emulator detects exception") for more details on KVM's limitations with respect to emulated MMIO during complex emulator flows Generic: - Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE, because the special casing needed by these pages is not due to just unmovability (and in fact they are only unmovable because the CPU cannot access them) - New ioctl to populate the KVM page tables in advance, which is useful to mitigate KVM page faults during guest boot or after live migration. The code will also be used by TDX, but (probably) not through the ioctl - Enable halt poll shrinking by default, as Intel found it to be a clear win - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out() - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout Selftests: - Remove dead code in the memslot modification stress test - Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs - Print the guest pseudo-RNG seed only when it changes, to avoid spamming the log for tests that create lots of VMs - Make the PMU counters test less flaky when counting LLC cache misses by doing CLFLUSH{OPT} in every loop iteration" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) crypto: ccp: Add the SNP_VLEK_LOAD command KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops KVM: x86: Replace static_call_cond() with static_call() KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event x86/sev: Move sev_guest.h into common SEV header KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event KVM: x86: Suppress MMIO that is triggered during task switch emulation KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory KVM: Document KVM_PRE_FAULT_MEMORY ioctl mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE perf kvm: Add kvm-stat for loongarch64 LoongArch: KVM: Add PV steal time support in guest side ...
2024-07-20Merge tag 'landlock-6.11-rc1' of ↵Linus Torvalds1-29/+37
git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux Pull landlock updates from Mickaël Salaün: "This simplifies code and improves documentation" * tag 'landlock-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux: landlock: Various documentation improvements landlock: Clarify documentation for struct landlock_ruleset_attr landlock: Use bit-fields for storing handled layer access masks
2024-07-20Merge tag 'char-misc-6.11-rc1' of ↵Linus Torvalds1-0/+22
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char / misc and other driver updates from Greg KH: "Here is the "big" set of char/misc and other driver subsystem changes for 6.11-rc1. Nothing major in here, just loads of new drivers and updates. Included in here are: - IIO api updates and new drivers added - wait_interruptable_timeout() api cleanups for some drivers - MODULE_DESCRIPTION() additions for loads of drivers - parport out-of-bounds fix - interconnect driver updates and additions - mhi driver updates and additions - w1 driver fixes - binder speedups and fixes - eeprom driver updates - coresight driver updates - counter driver update - new misc driver additions - other minor api updates All of these, EXCEPT for the final Kconfig build fix for 32bit systems, have been in linux-next for a while with no reported issues. The Kconfig fixup went in 29 hours ago, so might have missed the latest linux-next, but was acked by everyone involved" * tag 'char-misc-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (330 commits) misc: Kconfig: exclude mrvl-cn10k-dpi compilation for 32-bit systems misc: delete Makefile.rej binder: fix hang of unregistered readers misc: Kconfig: add a new dependency for MARVELL_CN10K_DPI virtio: add missing MODULE_DESCRIPTION() macro agp: uninorth: add missing MODULE_DESCRIPTION() macro spmi: add missing MODULE_DESCRIPTION() macros dev/parport: fix the array out-of-bounds risk samples: configfs: add missing MODULE_DESCRIPTION() macro misc: mrvl-cn10k-dpi: add Octeon CN10K DPI administrative driver misc: keba: Fix missing AUXILIARY_BUS dependency slimbus: Fix struct and documentation alignment in stream.c MAINTAINERS: CC dri-devel list on Qualcomm FastRPC patches misc: fastrpc: use coherent pool for untranslated Compute Banks misc: fastrpc: support complete DMA pool access to the DSP misc: fastrpc: add missing MODULE_DESCRIPTION() macro misc: fastrpc: Add missing dev_err newlines misc: fastrpc: Use memdup_user() nvmem: core: Implement force_ro sysfs attribute nvmem: Use sysfs_emit() for type attribute ...
2024-07-19random: note that RNDGETPOOL was removed in 2.6.9-rc2Jason A. Donenfeld1-1/+1
RNDGETPOOL was thankfully removed twenty years ago, but it's stuck around in headers. Probably removing it from uapi headers isn't great in case there are some weird users out there, but we should at least mark this as having been removed, to save future readers the same goose chase I just went on. Link: https://lore.kernel.org/all/E1By1St-0001TS-Qj@thunk.org/ Link: https://lore.kernel.org/all/Pine.LNX.4.58.0409130937050.4094@ppc970.osdl.org/ Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-07-19random: introduce generic vDSO getrandom() implementationJason A. Donenfeld1-0/+15
Provide a generic C vDSO getrandom() implementation, which operates on an opaque state returned by vgetrandom_alloc() and produces random bytes the same way as getrandom(). This has the following API signature: ssize_t vgetrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len); The return value and the first three arguments are the same as ordinary getrandom(), while the last two arguments are a pointer to the opaque allocated state and its size. Were all five arguments passed to the getrandom() syscall, nothing different would happen, and the functions would have the exact same behavior. The actual vDSO RNG algorithm implemented is the same one implemented by drivers/char/random.c, using the same fast-erasure techniques as that. Should the in-kernel implementation change, so too will the vDSO one. It requires an implementation of ChaCha20 that does not use any stack, in order to maintain forward secrecy if a multi-threaded program forks (though this does not account for a similar issue with SA_SIGINFO copying registers to the stack), so this is left as an architecture-specific fill-in. Stack-less ChaCha20 is an easy algorithm to implement on a variety of architectures, so this shouldn't be too onerous. Initially, the state is keyless, and so the first call makes a getrandom() syscall to generate that key, and then uses it for subsequent calls. By keeping track of a generation counter, it knows when its key is invalidated and it should fetch a new one using the syscall. Later, more than just a generation counter might be used. Since MADV_WIPEONFORK is set on the opaque state, the key and related state is wiped during a fork(), so secrets don't roll over into new processes, and the same state doesn't accidentally generate the same random stream. The generation counter, as well, is always >0, so that the 0 counter is a useful indication of a fork() or otherwise uninitialized state. If the kernel RNG is not yet initialized, then the vDSO always calls the syscall, because that behavior cannot be emulated in userspace, but fortunately that state is short lived and only during early boot. If it has been initialized, then there is no need to inspect the `flags` argument, because the behavior does not change post-initialization regardless of the `flags` value. Since the opaque state passed to it is mutated, vDSO getrandom() is not reentrant, when used with the same opaque state, which libc should be mindful of. The function works over an opaque per-thread state of a particular size, which must be marked VM_WIPEONFORK, VM_DONTDUMP, VM_NORESERVE, and VM_DROPPABLE for proper operation. Over time, the nuances of these allocations may change or grow or even differ based on architectural features. The opaque state passed to vDSO getrandom() must be allocated using the mmap_flags and mmap_prot parameters provided by the vgetrandom_opaque_params struct, which also contains the size of each state. That struct can be obtained with a call to vgetrandom(NULL, 0, 0, &params, ~0UL). Then, libc can call mmap(2) and slice up the returned array into a state per each thread, while ensuring that no single state straddles a page boundary. Libc is expected to allocate a chunk of these on first use, and then dole them out to threads as they're created, allocating more when needed. vDSO getrandom() provides the ability for userspace to generate random bytes quickly and safely, and is intended to be integrated into libc's thread management. As an illustrative example, the introduced code in the vdso_test_getrandom self test later in this series might be used to do the same outside of libc. In a libc the various pthread-isms are expected to be elided into libc internals. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-07-19mm: add MAP_DROPPABLE for designating always lazily freeable mappingsJason A. Donenfeld1-0/+1
The vDSO getrandom() implementation works with a buffer allocated with a new system call that has certain requirements: - It shouldn't be written to core dumps. * Easy: VM_DONTDUMP. - It should be zeroed on fork. * Easy: VM_WIPEONFORK. - It shouldn't be written to swap. * Uh-oh: mlock is rlimited. * Uh-oh: mlock isn't inherited by forks. - It shouldn't reserve actual memory, but it also shouldn't crash when page faulting in memory if none is available * Uh-oh: VM_NORESERVE means segfaults. It turns out that the vDSO getrandom() function has three really nice characteristics that we can exploit to solve this problem: 1) Due to being wiped during fork(), the vDSO code is already robust to having the contents of the pages it reads zeroed out midway through the function's execution. 2) In the absolute worst case of whatever contingency we're coding for, we have the option to fallback to the getrandom() syscall, and everything is fine. 3) The buffers the function uses are only ever useful for a maximum of 60 seconds -- a sort of cache, rather than a long term allocation. These characteristics mean that we can introduce VM_DROPPABLE, which has the following semantics: a) It never is written out to swap. b) Under memory pressure, mm can just drop the pages (so that they're zero when read back again). c) It is inherited by fork. d) It doesn't count against the mlock budget, since nothing is locked. e) If there's not enough memory to service a page fault, it's not fatal, and no signal is sent. This way, allocations used by vDSO getrandom() can use: VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE And there will be no problem with OOMing, crashing on overcommitment, using memory when not in use, not wiping on fork(), coredumps, or writing out to swap. In order to let vDSO getrandom() use this, expose these via mmap(2) as MAP_DROPPABLE. Note that this involves removing the MADV_FREE special case from sort_folio(), which according to Yu Zhao is unnecessary and will simply result in an extra call to shrink_folio_list() in the worst case. The chunk removed reenables the swapbacked flag, which we don't want for VM_DROPPABLE, and we can't conditionalize it here because there isn't a vma reference available. Finally, the provided self test ensures that this is working as desired. Cc: linux-mm@kvack.org Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>