[ Upstream commit 857282b819cbaa0675aaab1e7542e2c0579f52d7 ]
This patch fixes a NULL pointer dereference bug in brcmfmac that occurs
when a high 'sd_sgentry_align' value applies (e.g. 512) and a lot of queued SKBs
are sent from the pkt queue.
The problem is the number of entries in the pre-allocated sgtable, it is
nents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) >> 4 + 1.
Given the default [rt]xglom_size=32 it's actually 35 which is too small.
Worst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB
is added for each original SKB if tailroom isn't enough to hold tail_pad.
At least one sg entry is needed for each SKB. So, eventually the "skb_queue_walk loop"
in brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return
NULL and this causes the oops.
The patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle
the worst-case.
Btw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464
additional bytes of memory.
Signed-off-by: Norbert van Bolhuis <nvbolhuis@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20241107132903.13513-1-nvbolhuis@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d6e6b9218ced5249b9136833ef5ec3f554ec7fde ]
It seems that many webcams have buggy firmware and don't expose the
mic capture volume with the proper resolution. We have workarounds in
mixer.c, but judging from the numbers, those can be better managed as
global quirk flags.
Link: https://patch.msgid.link/20241105120220.5740-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit afe260df55ac280cd56306248cb6d8a6b0db095c ]
Under sriov, host driver will save and restore vf pci cfg space during
reset. And during device init, under sriov, pci_restore_state happens after
fullaccess released, and it can have race condition with mmio protection
enable from host side leading to missing interrupts.
So skip amdgpu_device_cache_pci_state for sriov.
Signed-off-by: Victor Zhao <Victor.Zhao@amd.com>
Acked-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7543c3e3b9b88212fcd0aaf5cab5588797bdc7de ]
radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock
otherwise, there's a possible deadlock scenario when
dma debug API is called holding rq_lock():
CPU0 CPU1 CPU2
dma_free_attrs()
check_unmap() add_dma_entry() __schedule() //out
(A) rq_lock()
get_hash_bucket()
(A) dma_entry_hash
check_sync()
(A) radix_lock() (W) dma_entry_hash
dma_entry_free()
(W) radix_lock()
// CPU2's one
(W) rq_lock()
CPU1 situation can happen when it extending radix tree and
it tries to wake up kswapd via wake_all_kswapd().
CPU2 situation can happen while perf_event_task_sched_out()
(i.e. dma sync operation is called while deleting perf_event using
etm and etr tmc which are Arm Coresight hwtracing driver backends).
To remove this possible situation, call dma_entry_free() after
put_hash_bucket() in check_unmap().
Reported-by: Denis Nikitin <denik@chromium.org>
Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/2WMS7BBSF5OZYB63VT44U5YWLFP5HL6U/#RWM6MLQX5ANBTEQ2PRM7OXCBGCE6NPWU
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 32e7ee293ff476c67b51be006e986021967bc525 ]
Need to dereference the atcs acpi buffer after
the method is executed, otherwise it will result in
a memory leak.
Signed-off-by: Prike Liang <Prike.Liang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8b22f048331dfd45fdfbf0efdfb1d43deff7518d ]
Port this change to vega20_ih.c:
commit afbf7955ff01 ("drm/amdgpu: clear RB_OVERFLOW bit when enabling interrupts")
Original commit message:
"Why:
Setting IH_RB_WPTR register to 0 will not clear the RB_OVERFLOW bit
if RB_ENABLE is not set.
How to fix:
Set WPTR_OVERFLOW_CLEAR bit after RB_ENABLE bit is set.
The RB_ENABLE bit is required to be set, together with
WPTR_OVERFLOW_ENABLE bit so that setting WPTR_OVERFLOW_CLEAR bit
would clear the RB_OVERFLOW."
Signed-off-by: Victor Lu <victorchengchi.lu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2320c9e6a768d135c7b0039995182bb1a4e4fd22 ]
drm_sched_job_init() has no control over how users allocate struct
drm_sched_job. Unfortunately, the function can also not set some struct
members such as job->sched.
This could theoretically lead to UB by users dereferencing the struct's
pointer members too early.
It is easier to debug such issues if these pointers are initialized to
NULL, so dereferencing them causes a NULL pointer exception.
Accordingly, drm_sched_entity_init() does precisely that and initializes
its struct with memset().
Initialize parameter "job" to 0 in drm_sched_job_init().
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241021105028.19794-2-pstanner@redhat.com
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9df99c395d0f55fb444ef39f4d6f194ca437d884 ]
sock_init_data() attaches the allocated sk pointer to the provided sock
object. If inet6_create() fails later, the sk object is released, but the
sock object retains the dangling sk pointer, which may cause use-after-free
later.
Clear the sock sk pointer on error.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-8-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9365fa510c6f82e3aa550a09d0c5c6b44dbc78ff ]
sock_init_data() attaches the allocated sk object to the provided sock
object. If inet_create() fails later, the sk object is freed, but the
sock object retains the dangling pointer, which may create use-after-free
later.
Clear the sk pointer in the sock object on error.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-7-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b4fcd63f6ef79c73cafae8cf4a114def5fc3d80d ]
sock_init_data() attaches the allocated sk object to the provided sock
object. If ieee802154_create() fails later, the allocated sk object is
freed, but the dangling pointer remains in the provided sock object, which
may allow use-after-free.
Clear the sk pointer in the sock object on error.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-6-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3945c799f12b8d1f49a3b48369ca494d981ac465 ]
bt_sock_alloc() attaches allocated sk object to the provided sock object.
If rfcomm_dlc_alloc() fails, we release the sk object, but leave the
dangling pointer in the sock object, which may cause use-after-free.
Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc().
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-4-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7c4f78cdb8e7501e9f92d291a7d956591bf73be9 ]
bt_sock_alloc() allocates the sk object and attaches it to the provided
sock object. On error l2cap_sock_alloc() frees the sk object, but the
dangling pointer is still attached to the sock object, which may create
use-after-free in other code.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-3-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 397006ba5d918f9b74e734867e8fddbc36dc2282 ]
The subsequent calculation of port_rate = speed * 1000 * BYTES_PER_KBIT,
where the BYTES_PER_KBIT is of type LL, may cause an overflow.
At least when speed = SPEED_20000, the expression to the left of port_rate
will be greater than INT_MAX.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Elena Salomatkina <esalomatkina@ispras.ru>
Link: https://patch.msgid.link/20241013124529.1043-1-esalomatkina@ispras.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a500f3751d3c861be7e4463c933cf467240cca5d ]
GCC 15 enables -Werror=unterminated-string-initialization by default.
This results in the following build error
drivers/gpu/drm/display/drm_dp_dual_mode_helper.c: In function ‘is_hdmi_adaptor’:
drivers/gpu/drm/display/drm_dp_dual_mode_helper.c:164:17: error: initializer-string for array of
‘char’ is too long [-Werror=unterminated-string-initialization]
164 | "DP-HDMI ADAPTOR\x04";
| ^~~~~~~~~~~~~~~~~~~~~
After discussion with Ville, the fix was to increase the size of
dp_dual_mode_hdmi_id array by one, so that it can accommodate the NULL
line character. This should let us build the kernel with GCC 15.
Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241002092311.942822-1-brahmajit.xyz@gmail.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a1e2da6a5072f8abe5b0feaa91a5bcd9dc544a04 ]
It is possible, although unlikely, that an integer overflow will occur
when the result of radeon_get_ib_value() is shifted to the left.
Avoid it by casting one of the operands to larger data type (u64).
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
Signed-off-by: Igor Artemiev <Igor.A.Artemiev@mcst.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b4e5646178e86665f5caef2894578600f597098a ]
We regularly get dmesg error reports of:
[ 18.184066] hdmi-audio-codec hdmi-audio-codec.3.auto: ASoC: error at snd_soc_dai_startup on i2s-hifi: -19
[ 18.184098] MAI: soc_pcm_open() failed (-19)
These are generated for any disconnected hdmi interface when pulseaudio
attempts to open the associated ALSA device (numerous times). Each open
generates a kernel error message, generating general log spam.
The error messages all come from _soc_pcm_ret in sound/soc/soc-pcm.c#L39
which suggests returning ENOTSUPP, rather that ENODEV will be quiet.
And indeed it is.
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-5-dave.stevenson@raspberrypi.com
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 87a2f10395c82c2b4687bb8611a6c5663a12f9e7 ]
Adds driver support for the USB-C model of Apple's Magic Trackpad 2.
The 2024 USB-C model is compatible with the existing Magic Trackpad 2
driver but has a different hardware ID.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219470
Signed-off-by: Callahan Kovacs <callahankovacs@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit cd068d51594d9635bf6688fc78717572b78bce6a ]
GIGASTONE Gaming Plus microSD cards manufactured on 02/2022 report that
they support poweroff notification and cache, but they are not working
correctly.
Flush Cache bit never gets cleared in sd_flush_cache() and Poweroff
Notification Ready bit also never gets set to 1 within 1 second from the
end of busy of CMD49 in sd_poweroff_notify().
This leads to I/O error and runtime PM error state.
I observed that the same card manufactured on 01/2024 works as expected.
This problem seems similar to the Kingston cards fixed with
commit c467c8f081 ("mmc: Add MMC_QUIRK_BROKEN_SD_CACHE for Kingston
Canvas Go Plus from 11/2019") and should be handled using quirks.
CID for the problematic card is here.
12345641535443002000000145016200
Manufacturer ID is 0x12 and defined as CID_MANFID_GIGASTONE as of now,
but would like comments on what naming is appropriate because MID list
is not public and not sure it's right.
Signed-off-by: Keita Aihara <keita.aihara@sony.com>
Link: https://lore.kernel.org/r/20240913094417.GA4191647@sony.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 61a830bc0ea69a05d8a4534f825c6aa618263649 ]
Add Dexatek Technology Ltd USB Video Grabber 1d19:6108 to the cx231xx
driver. This device is sold under the name "BAUHN DVD Maker (DK8723)" by
ALDI in Australia.
This device is similar to 1d19:6109, which is already included in cx231xx.
Both video and audio capture function correctly after installing the
patched cx231xx driver.
Patch Changelog
v1:
- Initial submission.
v2:
- Fix SoB + Improve subject.
v3:
- Rephrase message to not exceed 75 characters per line.
- Removed reference to external GitHub URL.
Signed-off-by: Rohan Barar <rohan.barar@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit de20037e1b3c2f2ca97b8c12b8c7bca8abd509a7 ]
Warning at every leaking bits can cause a flood of message, triggering
various stall-warning mechanisms to fire, including CSD locks, which
makes the machine to be unusable.
Track the bits that are being leaked, and only warn when a new bit is
set.
That said, this patch will help with the following issues:
1) It will tell us which bits are being set, so, it is easy to
communicate it back to vendor, and to do a root-cause analyzes.
2) It avoid the machine to be unusable, because, worst case
scenario, the user gets less than 60 WARNs (one per unhandled bit).
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20241001141020.2620361-1-leitao@debian.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 59458fa4ddb47e7891c61b4a928d13d5f5b00aa0 ]
Ran Xiaokai reports that with a KCSAN-enabled PREEMPT_RT kernel, we can see
splats like:
| BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
| in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
| preempt_count: 10002, expected: 0
| RCU nest depth: 0, expected: 0
| no locks held by swapper/1/0.
| irq event stamp: 156674
| hardirqs last enabled at (156673): [<ffffffff81130bd9>] do_idle+0x1f9/0x240
| hardirqs last disabled at (156674): [<ffffffff82254f84>] sysvec_apic_timer_interrupt+0x14/0xc0
| softirqs last enabled at (0): [<ffffffff81099f47>] copy_process+0xfc7/0x4b60
| softirqs last disabled at (0): [<0000000000000000>] 0x0
| Preemption disabled at:
| [<ffffffff814a3e2a>] paint_ptr+0x2a/0x90
| CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0+ #3
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
| Call Trace:
| <IRQ>
| dump_stack_lvl+0x7e/0xc0
| dump_stack+0x1d/0x30
| __might_resched+0x1a2/0x270
| rt_spin_lock+0x68/0x170
| kcsan_skip_report_debugfs+0x43/0xe0
| print_report+0xb5/0x590
| kcsan_report_known_origin+0x1b1/0x1d0
| kcsan_setup_watchpoint+0x348/0x650
| __tsan_unaligned_write1+0x16d/0x1d0
| hrtimer_interrupt+0x3d6/0x430
| __sysvec_apic_timer_interrupt+0xe8/0x3a0
| sysvec_apic_timer_interrupt+0x97/0xc0
| </IRQ>
On a detected data race, KCSAN's reporting logic checks if it should
filter the report. That list is protected by the report_filterlist_lock
*non-raw* spinlock which may sleep on RT kernels.
Since KCSAN may report data races in any context, convert it to a
raw_spinlock.
This requires being careful about when to allocate memory for the filter
list itself which can be done via KCSAN's debugfs interface. Concurrent
modification of the filter list via debugfs should be rare: the chosen
strategy is to optimistically pre-allocate memory before the critical
section and discard if unused.
Link: https://lore.kernel.org/all/20240925143154.2322926-1-ranxiaokai627@163.com/
Reported-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Tested-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 27141b690547da5650a420f26ec369ba142a9ebb ]
The PAC exec_sign_all() test spawns some child processes, creating pipes
to be stdin and stdout for the child. It cleans up most of the file
descriptors that are created as part of this but neglects to clean up the
parent end of the child stdin and stdout. Add the missing close() calls.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241111-arm64-pac-test-collisions-v1-1-171875f37e44@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 70958a949d852cbecc3d46127bf0b24786df0130 ]
If you follow the seed/sprout wiki, it suggests the following workflow:
btrfstune -S 1 seed_dev
mount seed_dev mnt
btrfs device add sprout_dev
mount -o remount,rw mnt
The first mount mounts the FS readonly, which results in not setting
BTRFS_FS_OPEN, and setting the readonly bit on the sb. The device add
somewhat surprisingly clears the readonly bit on the sb (though the
mount is still practically readonly, from the users perspective...).
Finally, the remount checks the readonly bit on the sb against the flag
and sees no change, so it does not run the code intended to run on
ro->rw transitions, leaving BTRFS_FS_OPEN unset.
As a result, when the cleaner_kthread runs, it sees no BTRFS_FS_OPEN and
does no work. This results in leaking deleted snapshots until we run out
of space.
I propose fixing it at the first departure from what feels reasonable:
when we clear the readonly bit on the sb during device add.
A new fstest I have written reproduces the bug and confirms the fix.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2e8b6bc0ab41ce41e6dfcc204b6cc01d5abbc952 ]
[PROBLEM]
It is very common for udev to trigger device scan, and every time a
mounted btrfs device got re-scan from different soft links, we will get
some of unnecessary device path updates, this is especially common
for LVM based storage:
# lvs
scratch1 test -wi-ao---- 10.00g
scratch2 test -wi-a----- 10.00g
scratch3 test -wi-a----- 10.00g
scratch4 test -wi-a----- 10.00g
scratch5 test -wi-a----- 10.00g
test test -wi-a----- 10.00g
# mkfs.btrfs -f /dev/test/scratch1
# mount /dev/test/scratch1 /mnt/btrfs
# dmesg -c
[ 205.705234] BTRFS: device fsid 7be2602f-9e35-4ecf-a6ff-9e91d2c182c9 devid 1 transid 6 /dev/mapper/test-scratch1 (253:4) scanned by mount (1154)
[ 205.710864] BTRFS info (device dm-4): first mount of filesystem 7be2602f-9e35-4ecf-a6ff-9e91d2c182c9
[ 205.711923] BTRFS info (device dm-4): using crc32c (crc32c-intel) checksum algorithm
[ 205.713856] BTRFS info (device dm-4): using free-space-tree
[ 205.722324] BTRFS info (device dm-4): checking UUID tree
So far so good, but even if we just touched any soft link of
"dm-4", we will get quite some unnecessary device path updates.
# touch /dev/mapper/test-scratch1
# dmesg -c
[ 469.295796] BTRFS info: devid 1 device path /dev/mapper/test-scratch1 changed to /dev/dm-4 scanned by (udev-worker) (1221)
[ 469.300494] BTRFS info: devid 1 device path /dev/dm-4 changed to /dev/mapper/test-scratch1 scanned by (udev-worker) (1221)
Such device path rename is unnecessary and can lead to random path
change due to the udev race.
[CAUSE]
Inside device_list_add(), we are using a very primitive way checking if
the device has changed, strcmp().
Which can never handle links well, no matter if it's hard or soft links.
So every different link of the same device will be treated as a different
device, causing the unnecessary device path update.
[FIX]
Introduce a helper, is_same_device(), and use path_equal() to properly
detect the same block device.
So that the different soft links won't trigger the rename race.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1230641
Reported-by: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a0bd7dacbd51c632b8e2c0500b479af564afadf3 ]
CPU hotplug remove handling triggers the following function
call sequence:
CPUHP_AP_PERF_S390_SF_ONLINE --> s390_pmu_sf_offline_cpu()
...
CPUHP_AP_PERF_ONLINE --> perf_event_exit_cpu()
The s390 CPUMF sampling CPU hotplug handler invokes:
s390_pmu_sf_offline_cpu()
+--> cpusf_pmu_setup()
+--> setup_pmc_cpu()
+--> deallocate_buffers()
This function de-allocates all sampling data buffers (SDBs) allocated
for that CPU at event initialization. It also clears the
PMU_F_RESERVED bit. The CPU is gone and can not be sampled.
With the event still being active on the removed CPU, the CPU event
hotplug support in kernel performance subsystem triggers the
following function calls on the removed CPU:
perf_event_exit_cpu()
+--> perf_event_exit_cpu_context()
+--> __perf_event_exit_context()
+--> __perf_remove_from_context()
+--> event_sched_out()
+--> cpumsf_pmu_del()
+--> cpumsf_pmu_stop()
+--> hw_perf_event_update()
to stop and remove the event. During removal of the event, the
sampling device driver tries to read out the remaining samples from
the sample data buffers (SDBs). But they have already been freed
(and may have been re-assigned). This may lead to a use after free
situation in which case the samples are most likely invalid. In the
best case the memory has not been reassigned and still contains
valid data.
Remedy this situation and check if the CPU is still in reserved
state (bit PMU_F_RESERVED set). In this case the SDBs have not been
released an contain valid data. This is always the case when
the event is removed (and no CPU hotplug off occured).
If the PMU_F_RESERVED bit is not set, the SDB buffers are gone.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
