kernel/linux.git/include, branch v3.18.51

perf: Avoid horrible stack usage

2017-04-30T03:49:15+00:00

commit 86038c5ea81b519a8a1fcfcd5e4599aab0cdd119 upstream. Both Linus (most recent) and Steve (a while ago) reported that perf related callbacks have massive stack bloat. The problem is that software events need a pt_regs in order to properly report the event location and unwind stack. And because we could not assume one was present we allocated one on stack and filled it with minimal bits required for operation. Now, pt_regs is quite large, so this is undesirable. Furthermore it turns out that most sites actually have a pt_regs pointer available, making this even more onerous, as the stack space is pointless waste. This patch addresses the problem by observing that software events have well defined nesting semantics, therefore we can use static per-cpu storage instead of on-stack. Linus made the further observation that all but the scheduler callers of perf_sw_event() have a pt_regs available, so we change the regular perf_sw_event() to require a valid pt_regs (where it used to be optional) and add perf_sw_event_sched() for the scheduler. We have a scheduler specific call instead of a more generic _noregs() like construct because we can assume non-recursion from the scheduler and thereby simplify the code further (_noregs would have to put the recursion context call inline in order to assertain which __perf_regs element to use). One last note on the implementation of perf_trace_buf_prepare(); we allow .regs = NULL for those cases where we already have a pt_regs pointer available and do not need another. Reported-by: Linus Torvalds Reported-by: Steven Rostedt Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Javi Merino Cc: Linus Torvalds Cc: Mathieu Desnoyers Cc: Oleg Nesterov Cc: Paul Mackerras Cc: Petr Mladek Cc: Steven Rostedt Cc: Tom Zanussi Cc: Vaibhav Nagarnaik Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

give up on gcc ilog2() constant optimizations

2017-04-22T05:15:07+00:00

commit 474c90156c8dcc2fa815e6716cc9394d7930cb9c upstream. gcc-7 has an "optimization" pass that completely screws up, and generates the code expansion for the (impossible) case of calling ilog2() with a zero constant, even when the code gcc compiles does not actually have a zero constant. And we try to generate a compile-time error for anybody doing ilog2() on a constant where that doesn't make sense (be it zero or negative). So now gcc7 will fail the build due to our sanity checking, because it created that constant-zero case that didn't actually exist in the source code. There's a whole long discussion on the kernel mailing about how to work around this gcc bug. The gcc people themselevs have discussed their "feature" in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785 but it's all water under the bridge, because while it looked at one point like it would be solved by the time gcc7 was released, that was not to be. So now we have to deal with this compiler braindamage. And the only simple approach seems to be to just delete the code that tries to warn about bad uses of ilog2(). So now "ilog2()" will just return 0 not just for the value 1, but for any non-positive value too. It's not like I can recall anybody having ever actually tried to use this function on any invalid value, but maybe the sanity check just meant that such code never made it out in public. Reported-by: Laura Abbott Cc: John Stultz , Cc: Thomas Gleixner Cc: Ard Biesheuvel Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

KVM: kvm_io_bus_unregister_dev() should never fail

2017-04-22T05:15:03+00:00

commit 90db10434b163e46da413d34db8d0e77404cc645 upstream. No caller currently checks the return value of kvm_io_bus_unregister_dev(). This is evil, as all callers silently go on freeing their device. A stale reference will remain in the io_bus, getting at least used again, when the iobus gets teared down on kvm_destroy_vm() - leading to use after free errors. There is nothing the callers could do, except retrying over and over again. So let's simply remove the bus altogether, print an error and make sure no one can access this broken bus again (returning -ENOMEM on any attempt to access it). Fixes: e93f8a0f821e ("KVM: convert io_bus to SRCU") Reported-by: Dmitry Vyukov Reviewed-by: Cornelia Huck Signed-off-by: David Hildenbrand Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

crypto: ahash - Fix EINPROGRESS notification callback

2017-04-22T05:15:01+00:00

commit ef0579b64e93188710d48667cb5e014926af9f1b upstream. The ahash API modifies the request's callback function in order to clean up after itself in some corner cases (unaligned final and missing finup). When the request is complete ahash will restore the original callback and everything is fine. However, when the request gets an EBUSY on a full queue, an EINPROGRESS callback is made while the request is still ongoing. In this case the ahash API will incorrectly call its own callback. This patch fixes the problem by creating a temporary request object on the stack which is used to relay EINPROGRESS back to the original completion function. This patch also adds code to preserve the original flags value. Fixes: ab6bf4e5e5e4 ("crypto: hash - Fix the pointer voodoo in...") Reported-by: Sabrina Dubroca Tested-by: Sabrina Dubroca Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman

scsi: libiscsi: add lock around task lists to fix list corruption regression

2017-04-22T05:15:01+00:00

commit 6f8830f5bbab16e54f261de187f3df4644a5b977 upstream. There's a rather long standing regression from the commit "libiscsi: Reduce locking contention in fast path" Depending on iSCSI target behavior, it's possible to hit the case in iscsi_complete_task where the task is still on a pending list (!list_empty(&task->running)). When that happens the task is removed from the list while holding the session back_lock, but other task list modification occur under the frwd_lock. That leads to linked list corruption and eventually a panicked system. Rather than back out the session lock split entirely, in order to try and keep some of the performance gains this patch adds another lock to maintain the task lists integrity. Major enterprise supported kernels have been backing out the lock split for while now, thanks to the efforts at IBM where a lab setup has the most reliable reproducer I've seen on this issue. This patch has been tested there successfully. Signed-off-by: Chris Leech Fixes: 659743b02c41 ("[SCSI] libiscsi: Reduce locking contention in fast path") Reported-by: Prashantha Subbarao Reviewed-by: Guilherme G. Piccoli Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

drm/ttm, drm/vmwgfx: Relax permission checking when opening surfaces

2017-04-22T05:14:59+00:00

commit fe25deb7737ce6c0879ccf79c99fa1221d428bf2 upstream. Previously, when a surface was opened using a legacy (non prime) handle, it was verified to have been created by a client in the same master realm. Relax this so that opening is also allowed recursively if the client already has the surface open. This works around a regression in svga mesa where opening of a shared surface is used recursively to obtain surface information. Signed-off-by: Thomas Hellstrom Reviewed-by: Sinclair Yeh Signed-off-by: Greg Kroah-Hartman

uapi: fix linux/packet_diag.h userspace compilation error

2017-04-18T05:55:54+00:00

commit 745cb7f8a5de0805cade3de3991b7a95317c7c73 upstream. Replace MAX_ADDR_LEN with its numeric value to fix the following linux/packet_diag.h userspace compilation error: /usr/include/linux/packet_diag.h:67:17: error: 'MAX_ADDR_LEN' undeclared here (not in a function) __u8 pdmc_addr[MAX_ADDR_LEN]; This is not the first case in the UAPI where the numeric value of MAX_ADDR_LEN is used instead of symbolic one, uapi/linux/if_link.h already does the same: $ grep MAX_ADDR_LEN include/uapi/linux/if_link.h __u8 mac[32]; /* MAX_ADDR_LEN */ There are no UAPI headers besides these two that use MAX_ADDR_LEN. Signed-off-by: Dmitry V. Levin Acked-by: Pavel Emelyanov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

usb-core: Add LINEAR_FRAME_INTR_BINTERVAL USB quirk

2017-04-18T05:55:53+00:00

commit 3243367b209faed5c320a4e5f9a565ee2a2ba958 upstream. Some USB 2.0 devices erroneously report millisecond values in bInterval. The generic config code manages to catch most of them, but in some cases it's not completely enough. The case at stake here is a USB 2.0 braille device, which wants to announce 10ms and thus sets bInterval to 10, but with the USB 2.0 computation that yields to 64ms. It happens that one can type fast enough to reach this interval and get the device buffers overflown, leading to problematic latencies. The generic config code does not catch this case because the 64ms is considered a sane enough value. This change thus adds a USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL quirk to mark devices which actually report milliseconds in bInterval, and marks Vario Ultra devices as needing it. Signed-off-by: Samuel Thibault Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

netlink: remove mmapped netlink support

2017-04-18T05:55:51+00:00

commit d1b4c689d4130bcfd3532680b64db562300716b6 upstream. mmapped netlink has a number of unresolved issues: - TX zerocopy support had to be disabled more than a year ago via commit 4682a0358639b29cf ("netlink: Always copy on mmap TX.") because the content of the mmapped area can change after netlink attribute validation but before message processing. - RX support was implemented mainly to speed up nfqueue dumping packet payload to userspace. However, since commit ae08ce0021087a5d812d2 ("netfilter: nfnetlink_queue: zero copy support") we avoid one copy with the socket-based interface too (via the skb_zerocopy helper). The other problem is that skbs attached to mmaped netlink socket behave different from normal skbs: - they don't have a shinfo area, so all functions that use skb_shinfo() (e.g. skb_clone) cannot be used. - reserving headroom prevents userspace from seeing the content as it expects message to start at skb->head. See for instance commit aa3a022094fa ("netlink: not trim skb for mmaped socket when dump"). - skbs handed e.g. to netlink_ack must have non-NULL skb->sk, else we crash because it needs the sk to check if a tx ring is attached. Also not obvious, leads to non-intuitive bug fixes such as 7c7bdf359 ("netfilter: nfnetlink: use original skbuff when acking batches"). mmaped netlink also didn't play nicely with the skb_zerocopy helper used by nfqueue and openvswitch. Daniel Borkmann fixed this via commit 6bb0fef489f6 ("netlink, mmap: fix edge-case leakages in nf queue zero-copy")' but at the cost of also needing to provide remaining length to the allocation function. nfqueue also has problems when used with mmaped rx netlink: - mmaped netlink doesn't allow use of nfqueue batch verdict messages. Problem is that in the mmap case, the allocation time also determines the ordering in which the frame will be seen by userspace (A allocating before B means that A is located in earlier ring slot, but this also means that B might get a lower sequence number then A since seqno is decided later. To fix this we would need to extend the spinlocked region to also cover the allocation and message setup which isn't desirable. - nfqueue can now be configured to queue large (GSO) skbs to userspace. Queing GSO packets is faster than having to force a software segmentation in the kernel, so this is a desirable option. However, with a mmap based ring one has to use 64kb per ring slot element, else mmap has to fall back to the socket path (NL_MMAP_STATUS_COPY) for all large packets. To use the mmap interface, userspace not only has to probe for mmap netlink support, it also has to implement a recv/socket receive path in order to handle messages that exceed the size of an rx ring element. Cc: Daniel Borkmann Cc: Ken-ichirou MATSUZAWA Cc: Pablo Neira Ayuso Cc: Patrick McHardy Cc: Thomas Graf Signed-off-by: Florian Westphal Signed-off-by: David S. Miller Cc: Shi Yuejie Signed-off-by: Greg Kroah-Hartman

tracing: Add #undef to fix compile error

2017-04-18T05:55:51+00:00

commit bf7165cfa23695c51998231c4efa080fe1d3548d upstream. There are several trace include files that define TRACE_INCLUDE_FILE. Include several of them in the same .c file (as I currently have in some code I am working on), and the compile will blow up with a "warning: "TRACE_INCLUDE_FILE" redefined #define TRACE_INCLUDE_FILE syscalls" Every other include file in include/trace/events/ avoids that issue by having a #undef TRACE_INCLUDE_FILE before the #define; syscalls.h should have one, too. Link: http://lkml.kernel.org/r/20160928225554.13bd7ac6@annuminas.surriel.com Fixes: b8007ef74222 ("tracing: Separate raw syscall from syscall tracer") Signed-off-by: Rik van Riel Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman