| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
media: rtl2832: fix use-after-free in rtl2832_remove()
cancel_delayed_work_sync() is called before i2c_mux_del_adapters()
in rtl2832_remove(). While the cancel waits for any running instance
of i2c_gate_work to finish, it does not prevent the timer from being
rescheduled by a concurrent thread.
During probe, the r820t_attach() call attempts I2C transfers through
the mux adapter. These transfers go through i2c_mux_master_xfer(),
which calls rtl2832_deselect() after the transfer completes,
rescheduling i2c_gate_work via schedule_delayed_work(). If this
transfer is still in flight when rtl2832_remove() runs,
rtl2832_deselect() can reschedule i2c_gate_work after it has been
cancelled, causing a use-after-free when kfree(dev) is called.
Fix this by calling i2c_mux_del_adapters() before
cancel_delayed_work_sync(). Once the mux adapter is unregistered, no
new I2C transfers can go through it, so rtl2832_deselect() can no
longer reschedule i2c_gate_work. The subsequent
cancel_delayed_work_sync() is then guaranteed to be final. |
| In the Linux kernel, the following vulnerability has been resolved:
media: saa7134: Fix a possible memory leak in saa7134_video_init1
In saa7134_video_init1(), the return value of the first
saa7134_pgtable_alloc() is not checked. If it fails, the function
continues as if successful, leaving the driver with an invalid page
table. Additionally, if vb2_queue_init() for the VBI queue fails after
the video queue page table has been allocated, the allocated memory is
not freed before returning. The second saa7134_pgtable_alloc() also
lacks a return value check. Errors occur during device probing before
the device is fully registered, the normal cleanup path in
saa7134_finidev() is not executed, leading to memory leaks and
potential use of uninitialized DMA resources.
Check the return value of both saa7134_pgtable_alloc() calls and
propagate errors. On failure of any later step, free allocated page
tables to avoid memory leaks. Ensure control handlers are also
released on error to prevent further resource leakage.
Found by code review. |
| In the Linux kernel, the following vulnerability has been resolved:
media: v4l2-fwnode: Fix subdev owner overwritten in v4l2_async_register_subdev_sensor()
The v4l2 helper v4l2_async_register_subdev_sensor() calls
v4l2_async_register_subdev(), which is a macro that expands to
__v4l2_async_register_subdev(sd,THIS_MODULE). Since the macro is expanded
inside v4l2-fwnode.c, THIS_MODULE resolves to the v4l2-fwnode module
rather than the sensor driver module that originally set sd->owner. When
v4l2-fwnode is built-in, THIS_MODULE evaluates to NULL, which then
overwrites the sensor driver's owner with NULL.
This causes the problem that the sensor module's reference count is never
incremented during async registration, so the module can be removed while
the subdevice is still in use by a notifier (e.g., a CSI-2 receiver
bridge driver).
Fix this by renaming v4l2_async_register_subdev_sensor() to
__v4l2_async_register_subdev_sensor() with an added explicit module
argument and introducing a wrapper macro:
#define v4l2_async_register_subdev_sensor(sd) \
__v4l2_async_register_subdev_sensor(sd, THIS_MODULE)
This ensures the sensor driver module is properly referenced even when
the sensor driver does not init the owner field before calling
v4l2_async_register_subdev_sensor() and prevents premature module removal. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: fix NULL dereference when the AP has HT-cap but no HT-oper
mwifiex_tdls_add_ht_oper() gates its follow-the-AP-bandwidth path on
bss_desc->bcn_ht_cap being present, but then dereferences a different
pointer, bss_desc->bcn_ht_oper:
if (ISSUPP_CHANWIDTH40(priv->adapter->hw_dot_11n_dev_cap) &&
bss_desc->bcn_ht_cap &&
ISALLOWED_CHANWIDTH40(bss_desc->bcn_ht_oper->ht_param))
bcn_ht_cap and bcn_ht_oper are populated independently while parsing the
associated AP's beacon in mwifiex_update_bss_desc_with_ie(): an AP that
advertises an HT Capabilities element but no HT Operation element leaves
bcn_ht_cap non-NULL and bcn_ht_oper NULL. Setting up a TDLS link to a
peer while associated to such an AP then dereferences the NULL
bcn_ht_oper and crashes the kernel. Every other bcn_ht_oper user in the
driver NULL-checks it first.
Guard on the pointer that is actually dereferenced.
Found by 0sec automated security-research tooling (https://0sec.ai). |
| In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: fix OOB reads in rtw_get_wps_ie()
rtw_get_wps_ie() iterates over IE data from network frames without
validating that the IE header and payload fit within the remaining
buffer before reading them. Specifically:
- in_ie[cnt + 1] is read without checking cnt + 1 < in_len
- memcmp(&in_ie[cnt + 2], ...) accesses cnt + 2 without bounds check
- in_ie[cnt + 1] is used as length without verifying payload fits
Add bounds checks at the top of the loop body to break early if fewer
than 2 bytes remain for the IE header, or if the declared payload
extends past the end of the buffer. Also require at least 4 bytes of
payload before comparing the WPS OUI. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: Fix session UAF in set_termios
rfcomm_tty_set_termios() tests dlc->session without rfcomm_mutex and
later passes the pointer to rfcomm_send_rpn(). The latter dereferences
both session->initiator and session->sock. Meanwhile, krfcommd can
unlink the DLC and free the session while holding rfcomm_mutex.
The race can proceed as follows:
TTY ioctl task krfcommd
-------------- --------
load dlc->session
enter rfcomm_send_rpn()
lock rfcomm_mutex
clear dlc->session
free session
unlock rfcomm_mutex
read session->initiator
KASAN reported:
BUG: KASAN: slab-use-after-free in rfcomm_send_rpn+0x297/0x2a0
Read of size 4 at addr ffff88810012a850 by task poc/92
Call Trace:
rfcomm_send_rpn+0x297/0x2a0
rfcomm_tty_set_termios+0x50d/0x850
tty_set_termios+0x596/0x950
set_termios+0x46a/0x6e0
tty_mode_ioctl+0x152/0xbd0
tty_ioctl+0x915/0x1240
__x64_sys_ioctl+0x134/0x1c0
Allocated by task 92:
rfcomm_session_add+0x9e/0x2e0
rfcomm_dlc_open+0x8b1/0xe00
rfcomm_dev_activate+0x85/0x1a0
rfcomm_tty_open+0x90/0x280
Freed by task 68:
kfree+0x131/0x3c0
rfcomm_session_del+0x119/0x180
rfcomm_run+0x737/0x4710
Add rfcomm_dlc_send_rpn(), which holds rfcomm_mutex while it verifies
that the DLC is still attached and sends the RPN frame. Have the TTY
path use the helper and drop its unlocked session check. This keeps the
session valid through both the frame construction and socket send. |
| In the Linux kernel, the following vulnerability has been resolved:
exec: fix unsigned loop counter wrap in transfer_args_to_stack()
The stop value is derived from bprm->p >> PAGE_SHIFT. The index variable
is an unsigned long. If bprm->p drops below PAGE_SIZE and stop becomes
zero the loop condition index >= stop is always true.
After the index == 0 iteration the decrement wraps to ULONG_MAX and
bprm->page[ULONG_MAX] reads sizeof(void *) bytes in front of the array.
The pointer has wrapped to -1. That garbage pointer is then passed to
kmap_local_page() and PAGE_SIZE bytes are copied from wherever that
lands into the stack of the process being created. And the loop doesn't
terminate either...
Getting there only requires bprm->p < PAGE_SIZE. On !MMU
bprm_set_stack_limit() and bprm_hit_stack_limit() are empty. So the only
constraint on how far bprm->p is pushed down is valid_arg_len(), i.e.
that each individual string still fits in what is left.
bprm->p starts at PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *) so a
single argument or environment string of a little over 31 pages leaves
it in the first page:
Oops - load access fault [#1]
CPU: 0 UID: 0 PID: 1 Comm: victim Not tainted 7.2.0-rc4 #1
epc : __memcpy+0xd4/0xf8
ra : transfer_args_to_stack+0xaa/0xae
s4 : ffffffffffffffff s2 : 0000000000000000
a1 : ffffffdc98000000 a2 : 0000000000001000
status: 0000000a00001880 badaddr: ffffffdc98000000 cause: 0000000000000005
[<801a5324>] __memcpy+0xd4/0xf8
[<800d5f6a>] load_flat_binary+0x43a/0x65e
[<800a2de4>] bprm_execve+0x1d4/0x316
[<800a351a>] do_execveat_common+0x12e/0x138
[<800a3d44>] __riscv_sys_execve+0x38/0x4e
Kernel panic - not syncing: Fatal exception in interrupt
This is an arcane bug but we should still fix it.
Count down from MAX_ARG_PAGES so the loop ends when index reaches stop,
stop == 0 included. The iterations performed are unchanged for every
other value of stop.
Only CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used
by binfmt_flat and binfmt_elf_fdpic on nommu only.
The loop predates git history. commit 7e7ec6a93434
("elf_fdpic_transfer_args_to_stack(): make it generic") only moved it
from binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used
part of the first page. The condition and the decrement are unchanged
from 2.6.12-rc2. |
| In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: set have_execfd only once the interpreter is opened
load_misc_binary() raises bprm->have_execfd as soon as it sees the 'O'
(or 'C') flag. This happens well before it opens the interpreter. If
that open fails the flag stays set on the bprm. binfmt_misc is at the
head of the format list so an interpreter open failure that returns
-ENOEXEC lets the search fall through to a later format. This means it
runs the matched binary directly having never staged an interpreter. So
bprm->executable is NULL while have_execfd falsely claims a descriptor
is present.
Consequently, begin_new_exec() dereferences the missing executable:
would_dump(bprm, bprm->executable);
and NULL derefs. Had it not, the hand-off later in the same function
would have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL
file with -ENOMEM. Both sites are past the point of no return so the
exec cannot be unwound either way.
This can be reached by unprivileged users as binfmt_misc can be mounted
in user namespaces. So a user can register an 'O' entry whose
interpreter lives on a FUSE mount, have the FUSE server fail the open
with -ENOEXEC and execute a native ELF file that matches the entry.
have_execfd only means anything alongside the executable it describes
which is not set until the interpreter has been opened and staged.
So lets raise it there, next to execfd_creds, which is already set at
that point. An open failure now leaves it clear, so the fallback format
derives credentials from the binary and emits no AT_EXECFD, as it would
for any native exec. The argv rewrite load_misc_binary() performs before
the open is still not undone. This means the binary sees the interpreter
path in argv[0] and its own path in argv[1] but that predates this
change and only became observable once the exec stopped faulting. |
| In the Linux kernel, the following vulnerability has been resolved:
cdrom: fix stack out-of-bounds read in CDROMVOLCTRL
mmc_ioctl_cdrom_volume() first reads the audio control mode page into a
32-byte stack buffer with cgc->buflen set to 24. If the device reports a
block descriptor, the function increases cgc->buflen to include that
descriptor and reads the page again.
For CDROMVOLCTRL, the function then builds a MODE SELECT parameter list
by moving cgc->buffer forward by offset - 8 bytes. This drops the block
descriptor from the outgoing payload and leaves a new 8-byte mode
parameter header in front of the audio control page. However, cgc->buflen
is left unchanged.
With a standard 8-byte block descriptor, cgc->buffer points at buffer + 8
but cgc->buflen remains 32. cdrom_mode_select() therefore asks the low
level packet path to write 32 bytes from that adjusted pointer, reading 8
bytes past the end of the 32-byte stack buffer.
This is not hit by CDROMVOLREAD, and CDROMVOLCTRL only triggers it on
drives that return a non-zero block descriptor length, which helps explain
why it has gone unnoticed. The overread is also sent to the device as
extra MODE SELECT payload, so it may not produce an obvious local failure.
Reduce cgc->buflen by the same amount as the buffer pointer adjustment so
the MODE SELECT transfer covers only the intended parameter list. |
| In the Linux kernel, the following vulnerability has been resolved:
intel_th: fix MSC output device reference leak
intel_th_output_open() looks up the output device with
bus_find_device_by_devt(), which returns the device with a reference that
must be dropped after use.
commit 95fc36a234da ("intel_th: fix device leak on output open()")
attempted to drop the reference from intel_th_output_release(). However,
a successful open replaces file->f_op with the output driver file
operations before returning, so close runs the output driver release
callback instead.
For MSC outputs, close runs intel_th_msc_release(), which only removes
the per-file iterator and does not drop the device reference taken by
intel_th_output_open(). Consequently, every successful MSC output open
leaks one device reference.
Drop the device reference from intel_th_msc_release(), which is the
release path actually used for MSC output files. Remove the now-unused
intel_th_output_release() callback from intel_th_output_fops. |
| In the Linux kernel, the following vulnerability has been resolved:
mptcp: pm: userspace: fix use-after-free in get_local_id
In mptcp_pm_userspace_get_local_id(), the address entry is looked up under
spinlock, but its id is read after dropping the lock. A concurrent deletion
can free the entry between the unlock and the read, leading to UAF.
The race window is narrow. It was reproduced only with a locally
constructed stress test that repeatedly overlaps an MP_JOIN SYN with a
MPTCP_PM_CMD_SUBFLOW_DESTROY request.
However, the KASAN report below confirms that the race is reachable:
[ 666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0
...
[ 666.319401] Call Trace:
[ 666.319405] <IRQ>
[ 666.319408] dump_stack_lvl+0x53/0x70
[ 666.319412] print_address_description.constprop.0+0x2c/0x3b0
[ 666.319418] print_report+0xbe/0x2b0
[ 666.319421] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319423] kasan_report+0xce/0x100
[ 666.319426] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319429] mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319433] mptcp_pm_get_local_id+0x371/0x440
...
[ 666.319821] Allocated by task 45539:
[ 666.319844] kasan_save_stack+0x33/0x60
[ 666.319855] kasan_save_track+0x14/0x30
[ 666.319858] __kasan_kmalloc+0x8f/0xa0
[ 666.319863] __kmalloc_noprof+0x1e7/0x520
[ 666.319867] sock_kmalloc+0xdf/0x130
[ 666.319885] sock_kmemdup+0x1b/0x40
[ 666.319888] mptcp_userspace_pm_append_new_local_addr+0x261/0x500
[ 666.319910] mptcp_pm_nl_announce_doit+0x16a/0x610
...
[ 666.319967] Freed by task 45560:
[ 666.319988] kasan_save_stack+0x33/0x60
[ 666.319991] kasan_save_track+0x14/0x30
[ 666.319994] kasan_save_free_info+0x3b/0x60
[ 666.319998] __kasan_slab_free+0x43/0x70
[ 666.320000] kfree+0x166/0x440
[ 666.320003] sock_kfree_s+0x1d/0x50
[ 666.320007] mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200
[ 666.320011] mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0
Fix by copying the id into a local variable while still holding the lock,
and use -1 as a "not found" sentinel. |
| In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: prevent registration of special VMAs
Vova Tokarev says:
userfaultfd allows registration on shadow stack VMAs. With userfaultfd
access, you can register on the shadow stack, discard a page ... and
inject a page with chosen return addresses via UFFDIO_COPY.
Update vma_can_userfault() to reject VM_SHADOW_STACK.
While on it, also reject VM_SPECIAL so that if a driver would implement
vm_uffd_ops, it wouldn't be possible to register special VMAs with
userfaultfd.
Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude
hugetlb VMAs from the check for VM_SPECIAL. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: validate ranges in damon_set_regions()
DAMON core logic assumes zero length regions don't exist. However, a few
DAMON API callers including DAMON_SYSFS, DAMON_RECLAIM and DAMON_LRU_SORT
allow users to set empty monitoring target regions. This could result in
WARN_ONCE() on CONFIG_DAMON_DEBUG_SANITY enabled kernel, and
divide-by-zero from damon_merge_two_regions().
For example, the WANR_ONCE() can be triggered like below.
# grep DAMON_DEBUG_SANITY /boot/config-$(uname -r)
# CONFIG_DAMON_DEBUG_SANITY=y
# damo start
# cd /sys/kernel/mm/damon/admin/kdamonds/0
# echo 0 > contexts/0/targets/0/regions/0/start
# echo 0 > contexts/0/targets/0/regions/0/end
# echo commit > state
# dmesg
[....]
[ 73.705780] ------------[ cut here ]------------
[ 73.707552] start 0 >= end 0
[ 73.708452] WARNING: mm/damon/core.c:359 at damon_new_region+0x6e/0x80, CPU#1: kdamond.0/758
[...]
All DAMON API callers eventually use damon_set_regions() to setup the
regions. Add the validation logic in the function. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: disallow overlapping input ranges for damon_set_regions()
damon_set_regions() assumes the input ranges are sorted by the address and
don't overlap each other. Hence the assumption was initially to be
explicitly validated. But commit 97d482f4592f ("mm/damon/sysfs: reuse
damon_set_regions() for regions setting") has mistakenly removed the
validation.
This can make DAMON behave in unexpected ways. At the best, the
monitoring results snapshot will just look weird since there will be
overlapping regions. DAMOS will also work weirdly, applying the same
action multiple times for overlapping regions, and make DAMOS quota weird.
More seriously, depending on the setup and regions updates sequence,
negative size regions can be made. It will trigger WARN_ONCE() if the
kernel is built with CONFIG_DAMON_DEBUG_SANITY=y. Depending on the
monitoring results, the negative size region can further trigger division
by zero in damon_merge_two_regions().
Note that some of the consequences including the WARN_ONCE() and the
divide by zero depend on commits that were introduced after the root cause
commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for
regions setting").
Fix the problems by checking the assumption and returning an error if
the input ranges don't meet the assumption.
The issue was discovered [1] by Sashiko. |
| In the Linux kernel, the following vulnerability has been resolved:
ftrace: Add global mutex to serialize trace_parser access
In ftrace, the trace_parser structure is allocated and initialized when
a trace file is opened, and is subsequently used across write and release
handlers to parse user input.
The affected handler paths and their specific functions are:
- Open paths: ftrace_regex_open(), ftrace_graph_open()
- Write paths: ftrace_regex_write(), ftrace_graph_write()
- Release paths: ftrace_regex_release(), ftrace_graph_release()
If userspace opens a trace file descriptor and shares it across multiple
threads, concurrent write calls will race on the parser's internal state,
specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted
input or undefined behavior.
Fix this by adding a global mutex, parser_lock, to serialize all access
to trace_parser across write and release paths, preventing concurrent
corruption of parser state. |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Use sender devcom for MPV master-up
After PCIe DPC recovery, mlx5 reloads the affected functions and
replays multiport affiliation events. In the reported failure, the
first relevant device error was:
pcieport 0000:10:01.1: DPC: containment event
pcieport 0000:10:01.1: PCIe Bus Error: severity=Uncorrected (Fatal)
pcieport 0000:10:01.1: [ 5] SDES (First)
mlx5 recovered the PCI functions and resumed 0000:11:00.1. During
that resume, RDMA multiport binding replayed
MLX5_DRIVER_EVENT_AFFILIATION_DONE and mlx5e sent
MPV_DEVCOM_MASTER_UP. The host then panicked with:
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: mlx5_devcom_comp_set_ready+0x5/0x40 [mlx5_core]
RDI: 0000000000000000
Call trace included:
mlx5_devcom_comp_set_ready
mlx5e_devcom_event_mpv
mlx5_devcom_send_event
mlx5_ib_bind_slave_port
mlx5r_mp_probe
mlx5_pci_resume
MPV devcom registration publishes mlx5e private data to the component
peer list before mlx5e_devcom_init_mpv() stores the returned component
device in priv->devcom. A concurrent master-up event can therefore
reach a peer whose private data is visible but whose priv->devcom
backpointer is still NULL.
MPV_DEVCOM_MASTER_UP already carries the sender/master mlx5e private
data as event_data. The ready bit is stored on the shared devcom
component, not on an individual peer. Use the sender devcom when
marking the MPV component ready.
This preserves the readiness transition while avoiding a NULL
dereference of the peer devcom pointer during affiliation replay after
PCI error recovery. |
| In the Linux kernel, the following vulnerability has been resolved:
ice: fix PTP Call Trace during PTP release
If a PF reset occurs when the PTP state is ICE_PTP_UNINIT, then
ice_ptp_rebuild() will update the state to ICE_PTP_ERROR. This will
result in the following PTP release call trace during driver unload:
kernel BUG at lib/list_debug.c:52!
ice_ptp_release+0x332/0x3c0 [ice]
ice_deinit_features.part.0+0x10e/0x120 [ice]
ice_remove+0x100/0x220 [ice]
This was observed when passing PF1 through to a VM. ice_ptp_init()
fails because ctrl_pf is NULL and sets the state to ICE_PTP_UNINIT.
Fix by detecting the ICE_PTP_UNINIT state in ice_ptp_rebuild() and
returning without error, preventing the invalid state transition to
ICE_PTP_ERROR. The only valid path to ICE_PTP_ERROR is from
ICE_PTP_RESETTING after a failed rebuild. |
| In the Linux kernel, the following vulnerability has been resolved:
super: fix emergency thaw deadlock on frozen block devices
do_thaw_all_callback() calls bdev_thaw() while holding sb->s_umount
exclusively. If the block device was frozen via bdev_freeze() dropping
the last block layer freeze reference calls fs_bdev_thaw() which
reacquires s_umount:
do_thaw_all_callback(sb)
super_lock_excl(sb) # holds sb->s_umount
bdev_thaw(sb->s_bdev)
mutex_lock(&bdev->bd_fsfreeze_mutex)
# bd_fsfreeze_count drops 1 -> 0
bd_holder_ops->thaw == fs_bdev_thaw
get_bdev_super(bdev)
bdev_super_lock(bdev, true)
super_lock(sb, true)
down_write(&sb->s_umount) # same task: deadlock
The emergency thaw worker deadlocks against itself holding both
s_umount and bd_fsfreeze_mutex. That fscks any subsequent unmount,
freeze, or thaw of that filesystem and block device.
[ 81.878470] sysrq: Show Blocked State
[ 81.880140] task:kworker/0:1 state:D stack:0 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000
[ 81.884876] Workqueue: events do_thaw_all
[ 81.886656] Call Trace:
[ 81.887759] <TASK>
[ 81.888763] __schedule+0x579/0x1420
[ 81.890372] schedule+0x3a/0x100
[ 81.891794] schedule_preempt_disabled+0x15/0x30
[ 81.893848] rwsem_down_write_slowpath+0x1ea/0x900
[ 81.895191] ? __pfx_do_thaw_all_callback+0x10/0x10
[ 81.896528] down_write+0xbd/0xc0
[ 81.897505] super_lock+0x91/0x180
[ 81.898457] ? __mutex_lock+0xa99/0x1140
[ 81.900748] ? __mutex_unlock_slowpath+0x1f/0x400
[ 81.902069] bdev_super_lock+0x5b/0x150
[ 81.903132] get_bdev_super+0x10/0x60
[ 81.904042] fs_bdev_thaw+0x23/0xf0
[ 81.904755] bdev_thaw+0x82/0x100
[ 81.905484] do_thaw_all_callback+0x2c/0x50
[ 81.906298] __iterate_supers+0x5d/0x130
[ 81.907067] do_thaw_all+0x20/0x40
[ 81.907739] process_one_work+0x206/0x5e0
[ 81.908545] worker_thread+0x1e2/0x3c0
[ 81.909339] ? __pfx_worker_thread+0x10/0x10
[ 81.910171] kthread+0xf4/0x130
[ 81.910799] ? __pfx_kthread+0x10/0x10
[ 81.911528] ret_from_fork+0x2e2/0x3b0
[ 81.912259] ? __pfx_kthread+0x10/0x10
[ 81.913010] ret_from_fork_asm+0x1a/0x30
[ 81.913806] </TASK>
bdev_super_lock() even documents the violated requirement with
lockdep_assert_not_held(&sb->s_umount).
Acquiring bd_fsfreeze_mutex under s_umount also inverts the
bd_fsfreeze_mutex vs. s_umount ordering established by
bdev_{freeze,thaw}() and can thus ABBA against a concurrent block-layer
freeze even when the recursive path isn't hit.
Fix this by not holding s_umount around the bdev_thaw() loop at all. Pin
the superblock with an active reference instead as
filesystems_freeze_callback() does. The active reference keeps the
superblock from being shut down and so ->s_bdev stays valid without
holding s_umount. The block-layer-held freeze is dropped by
fs_bdev_thaw() with FREEZE_MAY_NEST | FREEZE_HOLDER_USERSPACE exactly as
a regular unfreeze would and thaw_super_locked() handles
filesystem-level freezes as before.
The emergency thaw path has deadlocked like this in one form or
another for a long long time but the current exclusively-held
shape dates back to commit [1] where thaw_bdev() already ended in
thaw_super() with s_umount held by do_thaw_all_callback(). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/gfx10: replace BUG_ON() with WARN_ON()
There's no need to crash the kernel for these cases.
(cherry picked from commit ac6f00beb658239bced4aaed9efbb04a35348d48) |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/gfx9: replace BUG_ON() with WARN_ON()
There's no need to crash the kernel for these cases.
(cherry picked from commit b71604f8685b0eba07866f4e8dc30f93e1931054) |
