<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git, branch v5.10.122</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.122</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.122'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2022-06-14T16:32:47+00:00</updated>
<entry>
<title>Linux 5.10.122</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2022-06-14T16:32:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5754c570a569d3f31e874abbf08dae1218a7431c'/>
<id>urn:sha1:5754c570a569d3f31e874abbf08dae1218a7431c</id>
<content type='text'>
Link: https://lore.kernel.org/r/20220613094850.166931805@linuxfoundation.org
Tested-by: Pavel Machek (CIP) &lt;pavel@denx.de&gt;
Link: https://lore.kernel.org/r/20220613181850.655683495@linuxfoundation.org
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Tested-by: Fox Chen &lt;foxhlchen@gmail.com&gt;
Tested-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Tested-by: Sudip Mukherjee &lt;sudip.mukherjee@codethink.co.uk&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>tcp: fix tcp_mtup_probe_success vs wrong snd_cwnd</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-05-27T21:28:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9ba2b4ac35935f05ac98cff722f36ba07d62270e'/>
<id>urn:sha1:9ba2b4ac35935f05ac98cff722f36ba07d62270e</id>
<content type='text'>
commit 11825765291a93d8e7f44230da67b9f607c777bf upstream.

syzbot got a new report [1] finally pointing to a very old bug,
added in initial support for MTU probing.

tcp_mtu_probe() has checks about starting an MTU probe if
tcp_snd_cwnd(tp) &gt;= 11.

But nothing prevents tcp_snd_cwnd(tp) to be reduced later
and before the MTU probe succeeds.

This bug would lead to potential zero-divides.

Debugging added in commit 40570375356c ("tcp: add accessors
to read/set tp-&gt;snd_cwnd") has paid off :)

While we are at it, address potential overflows in this code.

[1]
WARNING: CPU: 1 PID: 14132 at include/net/tcp.h:1219 tcp_mtup_probe_success+0x366/0x570 net/ipv4/tcp_input.c:2712
Modules linked in:
CPU: 1 PID: 14132 Comm: syz-executor.2 Not tainted 5.18.0-syzkaller-07857-gbabf0bb978e3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcp_snd_cwnd_set include/net/tcp.h:1219 [inline]
RIP: 0010:tcp_mtup_probe_success+0x366/0x570 net/ipv4/tcp_input.c:2712
Code: 74 08 48 89 ef e8 da 80 17 f9 48 8b 45 00 65 48 ff 80 80 03 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 aa b0 c5 f8 &lt;0f&gt; 0b e9 16 fe ff ff 48 8b 4c 24 08 80 e1 07 38 c1 0f 8c c7 fc ff
RSP: 0018:ffffc900079e70f8 EFLAGS: 00010287
RAX: ffffffff88c0f7f6 RBX: ffff8880756e7a80 RCX: 0000000000040000
RDX: ffffc9000c6c4000 RSI: 0000000000031f9e RDI: 0000000000031f9f
RBP: 0000000000000000 R08: ffffffff88c0f606 R09: ffffc900079e7520
R10: ffffed101011226d R11: 1ffff1101011226c R12: 1ffff1100eadcf50
R13: ffff8880756e72c0 R14: 1ffff1100eadcf89 R15: dffffc0000000000
FS:  00007f643236e700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ab3f1e2a0 CR3: 0000000064fe7000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 &lt;TASK&gt;
 tcp_clean_rtx_queue+0x223a/0x2da0 net/ipv4/tcp_input.c:3356
 tcp_ack+0x1962/0x3c90 net/ipv4/tcp_input.c:3861
 tcp_rcv_established+0x7c8/0x1ac0 net/ipv4/tcp_input.c:5973
 tcp_v6_do_rcv+0x57b/0x1210 net/ipv6/tcp_ipv6.c:1476
 sk_backlog_rcv include/net/sock.h:1061 [inline]
 __release_sock+0x1d8/0x4c0 net/core/sock.c:2849
 release_sock+0x5d/0x1c0 net/core/sock.c:3404
 sk_stream_wait_memory+0x700/0xdc0 net/core/stream.c:145
 tcp_sendmsg_locked+0x111d/0x3fc0 net/ipv4/tcp.c:1410
 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1448
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 __sys_sendto+0x439/0x5c0 net/socket.c:2119
 __do_sys_sendto net/socket.c:2131 [inline]
 __se_sys_sendto net/socket.c:2127 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2127
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f6431289109
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f643236e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f643139c100 RCX: 00007f6431289109
RDX: 00000000d0d0c2ac RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00007f64312e308d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff372533af R14: 00007f643236e300 R15: 0000000000022000

Fixes: 5d424d5a674f ("[TCP]: MTU probing")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Acked-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>dmaengine: idxd: add missing callback function to support DMA_INTERRUPT</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Dave Jiang</name>
<email>dave.jiang@intel.com</email>
</author>
<published>2022-04-26T22:32:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5e34b4975669451f731ec20b8c0e8c3431d691b3'/>
<id>urn:sha1:5e34b4975669451f731ec20b8c0e8c3431d691b3</id>
<content type='text'>
commit 2112b8f4fb5cc35d1c384324763765953186b81f upstream.

When setting DMA_INTERRUPT capability, a callback function
dma-&gt;device_prep_dma_interrupt() is needed to support this capability.
Without setting the callback, dma_async_device_register() will fail dma
capability check.

Fixes: 4e5a4eb20393 ("dmaengine: idxd: set DMA_INTERRUPT cap bit")
Signed-off-by: Dave Jiang &lt;dave.jiang@intel.com&gt;
Link: https://lore.kernel.org/r/165101232637.3951447.15765792791591763119.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul &lt;vkoul@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>zonefs: fix handling of explicit_open option on mount</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>damien.lemoal@opensource.wdc.com</email>
</author>
<published>2022-06-02T14:16:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b8c17121f05b542eb6f315a97adbb91060dfb53a'/>
<id>urn:sha1:b8c17121f05b542eb6f315a97adbb91060dfb53a</id>
<content type='text'>
commit a2a513be7139b279f1b5b2cee59c6c4950c34346 upstream.

Ignoring the explicit_open mount option on mount for devices that do not
have a limit on the number of open zones must be done after the mount
options are parsed and set in s_mount_opts. Move the check to ignore
the explicit_open option after the call to zonefs_parse_options() in
zonefs_fill_super().

Fixes: b5c00e975779 ("zonefs: open/close zone on file open/close")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>PCI: qcom: Fix pipe clock imbalance</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Johan Hovold</name>
<email>johan+linaro@kernel.org</email>
</author>
<published>2022-04-01T13:33:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ef51997771d698e2183c17d5a39a40e107d8ce88'/>
<id>urn:sha1:ef51997771d698e2183c17d5a39a40e107d8ce88</id>
<content type='text'>
commit fdf6a2f533115ec5d4d9629178f8196331f1ac50 upstream.

Fix a clock imbalance introduced by ed8cc3b1fc84 ("PCI: qcom: Add support
for SDM845 PCIe controller"), which enables the pipe clock both in init()
and in post_init() but only disables in post_deinit().

Note that the pipe clock was also never disabled in the init() error
paths and that enabling the clock before powering up the PHY looks
questionable.

Link: https://lore.kernel.org/r/20220401133351.10113-1-johan+linaro@kernel.org
Fixes: ed8cc3b1fc84 ("PCI: qcom: Add support for SDM845 PCIe controller")
Signed-off-by: Johan Hovold &lt;johan+linaro@kernel.org&gt;
Signed-off-by: Lorenzo Pieralisi &lt;lorenzo.pieralisi@arm.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Cc: stable@vger.kernel.org      # 5.6
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>md/raid0: Ignore RAID0 layout if the second zone has only one device</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Pascal Hambourg</name>
<email>pascal@plouf.fr.eu.org</email>
</author>
<published>2022-04-13T06:53:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=63bcb9da91eb0aba2e87022200f9b9aa45c4c111'/>
<id>urn:sha1:63bcb9da91eb0aba2e87022200f9b9aa45c4c111</id>
<content type='text'>
commit ea23994edc4169bd90d7a9b5908c6ccefd82fa40 upstream.

The RAID0 layout is irrelevant if all members have the same size so the
array has only one zone. It is *also* irrelevant if the array has two
zones and the second zone has only one device, for example if the array
has two members of different sizes.

So in that case it makes sense to allow assembly even when the layout is
undefined, like what is done when the array has only one zone.

Reviewed-by: NeilBrown &lt;neilb@suse.de&gt;
Signed-off-by: Pascal Hambourg &lt;pascal@plouf.fr.eu.org&gt;
Signed-off-by: Song Liu &lt;song@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>interconnect: Restore sync state by ignoring ipa-virt in provider count</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Stephen Boyd</name>
<email>swboyd@chromium.org</email>
</author>
<published>2022-06-08T20:54:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=418db40cc753aba2d92ff6f1d4f04cd39da64da8'/>
<id>urn:sha1:418db40cc753aba2d92ff6f1d4f04cd39da64da8</id>
<content type='text'>
commit 20ce30fb4750f2ffc130cdcb26232b1dd87cd0a5 upstream.

Ignore compatible strings for the IPA virt drivers that were removed in
commits 2fb251c26560 ("interconnect: qcom: sdx55: Drop IP0
interconnects") and 2f3724930eb4 ("interconnect: qcom: sc7180: Drop IP0
interconnects") so that the sync state logic can kick in again.
Otherwise all the interconnects in the system will stay pegged at max
speeds because 'providers_count' is always going to be one larger than
the number of drivers that will ever probe on sc7180 or sdx55. This
fixes suspend on sc7180 and sdx55 devices when you don't have a
devicetree patch to remove the ipa-virt compatible node.

Cc: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Cc: Doug Anderson &lt;dianders@chromium.org&gt;
Cc: Alex Elder &lt;elder@linaro.org&gt;
Cc: Taniya Das &lt;quic_tdas@quicinc.com&gt;
Cc: Mike Tipton &lt;quic_mdtipton@quicinc.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	# 5.10.x
Fixes: 2fb251c26560 ("interconnect: qcom: sdx55: Drop IP0 interconnects")
Fixes: 2f3724930eb4 ("interconnect: qcom: sc7180: Drop IP0 interconnects")
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Reviewed-by: Alex Elder &lt;elder@linaro.org&gt;
Reviewed-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Link: https://lore.kernel.org/r/20220427013226.341209-1-swboyd@chromium.org
Signed-off-by: Georgi Djakov &lt;djakov@kernel.org&gt;
Signed-off-by: Alex Elder &lt;elder@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>interconnect: qcom: sc7180: Drop IP0 interconnects</title>
<updated>2022-06-14T16:32:47+00:00</updated>
<author>
<name>Stephen Boyd</name>
<email>swboyd@chromium.org</email>
</author>
<published>2022-06-08T20:54:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=bcae8f8338abb2885dd1967f1be7b40c3aa23d4a'/>
<id>urn:sha1:bcae8f8338abb2885dd1967f1be7b40c3aa23d4a</id>
<content type='text'>
commit 2f3724930eb4bba74f7d10bc3bef5bb22dd323df upstream.

The IPA BCM resource ("IP0") on sc7180 was moved to the clk-rpmh driver
in commit bcd63d222b60 ("clk: qcom: rpmh: Add IPA clock for SC7180") and
modeled as a clk, but this interconnect driver still had it modeled as
an interconnect. This was mostly OK because nobody used the interconnect
definition, until the interconnect framework started dropping bandwidth
requests on interconnects that aren't used via the sync_state callback
in commit 7d3b0b0d8184 ("interconnect: qcom: Use icc_sync_state"). Once
that patch was applied the IP0 resource was going to be controlled from
two places, the clk framework and the interconnect framework.

Even then, things were probably going to be OK, because commit
b95b668eaaa2 ("interconnect: qcom: icc-rpmh: Add BCMs to commit list in
pre_aggregate") was needed to actually drop bandwidth requests on unused
interconnects, of which the IPA was one of the interconnect that wasn't
getting dropped to zero. Combining the three commits together leads to
bad behavior where the interconnect framework is disabling the IP0
resource because it has no users while the clk framework thinks the IP0
resource is on because the only user, the IPA driver, has turned it on
via clk_prepare_enable(). Depending on when sync_state is called, we can
get into a situation like below:

  IPA driver probes
  IPA driver gets notified modem started
   runtime PM get()
    IPA clk enabled -&gt; IP0 resource is ON
  sync_state runs
   interconnect zeroes out the IP0 resource -&gt; IP0 resource is off
  IPA driver tries to access a register and blows up

The crash is an unclocked access that manifest as an SError.

 SError Interrupt on CPU0, code 0xbe000011 -- SError
 CPU: 0 PID: 3595 Comm: mmdata_mgr Not tainted 5.17.1+ #166
 Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
 pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : mutex_lock+0x4c/0x80
 lr : mutex_lock+0x30/0x80
 sp : ffffffc00da9b9c0
 x29: ffffffc00da9b9c0 x28: 0000000000000000 x27: 0000000000000000
 x26: ffffffc00da9bc90 x25: ffffff80c2024010 x24: ffffff80c2024000
 x23: ffffff8083100000 x22: ffffff80831000d0 x21: ffffff80831000a8
 x20: ffffff80831000a8 x19: ffffff8083100070 x18: 00000000ffff0a00
 x17: 000000002f7254f1 x16: 0000000000000100 x15: 0000000000000000
 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
 x11: 000000000001f0b8 x10: ffffffc00931f0b8 x9 : 0000000000000000
 x8 : 0000000000000000 x7 : fefefefefeff2f60 x6 : 0000808080808080
 x5 : 0000000000000000 x4 : 8080808080800000 x3 : ffffff80d2d4ee28
 x2 : ffffff808c1d6e40 x1 : 0000000000000000 x0 : ffffff8083100070
 Kernel panic - not syncing: Asynchronous SError Interrupt
 CPU: 0 PID: 3595 Comm: mmdata_mgr Not tainted 5.17.1+ #166
 Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
 Call trace:
  dump_backtrace+0xf4/0x114
  show_stack+0x24/0x30
  dump_stack_lvl+0x64/0x7c
  dump_stack+0x18/0x38
  panic+0x150/0x38c
  nmi_panic+0x88/0xa0
  arm64_serror_panic+0x74/0x80
  do_serror+0x0/0x80
  do_serror+0x58/0x80
  el1h_64_error_handler+0x34/0x4c
  el1h_64_error+0x78/0x7c
  mutex_lock+0x4c/0x80
  __gsi_channel_start+0x50/0x17c
  gsi_channel_start+0x54/0x90
  ipa_endpoint_enable_one+0x34/0xc0
  ipa_open+0x4c/0x120

Remove all IP0 resource management from the interconnect driver so that
clk-rpmh is the sole owner. This fixes the issue by preventing the
interconnect driver from overwriting the IP0 resource data that the
clk-rpmh driver wrote.

Cc: Alex Elder &lt;elder@linaro.org&gt;
Cc: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Cc: Taniya Das &lt;quic_tdas@quicinc.com&gt;
Cc: Mike Tipton &lt;quic_mdtipton@quicinc.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	# 5.10.x
Fixes: b95b668eaaa2 ("interconnect: qcom: icc-rpmh: Add BCMs to commit list in pre_aggregate")
Fixes: bcd63d222b60 ("clk: qcom: rpmh: Add IPA clock for SC7180")
Fixes: 7d3b0b0d8184 ("interconnect: qcom: Use icc_sync_state")
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Tested-by: Alex Elder &lt;elder@linaro.org&gt;
Reviewed-by: Alex Elder &lt;elder@linaro.org&gt;
Reviewed-by: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Link: https://lore.kernel.org/r/20220412220033.1273607-2-swboyd@chromium.org
Signed-off-by: Georgi Djakov &lt;djakov@kernel.org&gt;
Signed-off-by: Alex Elder &lt;elder@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>powerpc/mm: Switch obsolete dssall to .long</title>
<updated>2022-06-14T16:32:46+00:00</updated>
<author>
<name>Alexey Kardashevskiy</name>
<email>aik@ozlabs.ru</email>
</author>
<published>2021-12-21T05:59:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=fe6caf512261d2cf81cd44bfe3ec4370f6256135'/>
<id>urn:sha1:fe6caf512261d2cf81cd44bfe3ec4370f6256135</id>
<content type='text'>
commit d51f86cfd8e378d4907958db77da3074f6dce3ba upstream.

The dssall ("Data Stream Stop All") instruction is obsolete altogether
with other Data Cache Instructions since ISA 2.03 (year 2006).

LLVM IAS does not support it but PPC970 seems to be using it.
This switches dssall to .long as there is no much point in fixing LLVM.

Signed-off-by: Alexey Kardashevskiy &lt;aik@ozlabs.ru&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20211221055904.555763-6-aik@ozlabs.ru
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>powerpc/32: Fix overread/overwrite of thread_struct via ptrace</title>
<updated>2022-06-14T16:32:46+00:00</updated>
<author>
<name>Michael Ellerman</name>
<email>mpe@ellerman.id.au</email>
</author>
<published>2022-06-06T14:34:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3be74fc0afbeadc2aff8dc69f3bf9716fbe66486'/>
<id>urn:sha1:3be74fc0afbeadc2aff8dc69f3bf9716fbe66486</id>
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commit 8e1278444446fc97778a5e5c99bca1ce0bbc5ec9 upstream.

The ptrace PEEKUSR/POKEUSR (aka PEEKUSER/POKEUSER) API allows a process
to read/write registers of another process.

To get/set a register, the API takes an index into an imaginary address
space called the "USER area", where the registers of the process are
laid out in some fashion.

The kernel then maps that index to a particular register in its own data
structures and gets/sets the value.

The API only allows a single machine-word to be read/written at a time.
So 4 bytes on 32-bit kernels and 8 bytes on 64-bit kernels.

The way floating point registers (FPRs) are addressed is somewhat
complicated, because double precision float values are 64-bit even on
32-bit CPUs. That means on 32-bit kernels each FPR occupies two
word-sized locations in the USER area. On 64-bit kernels each FPR
occupies one word-sized location in the USER area.

Internally the kernel stores the FPRs in an array of u64s, or if VSX is
enabled, an array of pairs of u64s where one half of each pair stores
the FPR. Which half of the pair stores the FPR depends on the kernel's
endianness.

To handle the different layouts of the FPRs depending on VSX/no-VSX and
big/little endian, the TS_FPR() macro was introduced.

Unfortunately the TS_FPR() macro does not take into account the fact
that the addressing of each FPR differs between 32-bit and 64-bit
kernels. It just takes the index into the "USER area" passed from
userspace and indexes into the fp_state.fpr array.

On 32-bit there are 64 indexes that address FPRs, but only 32 entries in
the fp_state.fpr array, meaning the user can read/write 256 bytes past
the end of the array. Because the fp_state sits in the middle of the
thread_struct there are various fields than can be overwritten,
including some pointers. As such it may be exploitable.

It has also been observed to cause systems to hang or otherwise
misbehave when using gdbserver, and is probably the root cause of this
report which could not be easily reproduced:
  https://lore.kernel.org/linuxppc-dev/dc38afe9-6b78-f3f5-666b-986939e40fc6@keymile.com/

Rather than trying to make the TS_FPR() macro even more complicated to
fix the bug, or add more macros, instead add a special-case for 32-bit
kernels. This is more obvious and hopefully avoids a similar bug
happening again in future.

Note that because 32-bit kernels never have VSX enabled the code doesn't
need to consider TS_FPRWIDTH/OFFSET at all. Add a BUILD_BUG_ON() to
ensure that 32-bit &amp;&amp; VSX is never enabled.

Fixes: 87fec0514f61 ("powerpc: PTRACE_PEEKUSR/PTRACE_POKEUSER of FPR registers in little endian builds")
Cc: stable@vger.kernel.org # v3.13+
Reported-by: Ariel Miculas &lt;ariel.miculas@belden.com&gt;
Tested-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20220609133245.573565-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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