| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
dm: fix NULL pointer dereference in __dm_suspend()
There is a race condition between dm device suspend and table load that
can lead to null pointer dereference. The issue occurs when suspend is
invoked before table load completes:
BUG: kernel NULL pointer dereference, address: 0000000000000054
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50
Call Trace:
<TASK>
blk_mq_quiesce_queue+0x2c/0x50
dm_stop_queue+0xd/0x20
__dm_suspend+0x130/0x330
dm_suspend+0x11a/0x180
dev_suspend+0x27e/0x560
ctl_ioctl+0x4cf/0x850
dm_ctl_ioctl+0xd/0x20
vfs_ioctl+0x1d/0x50
__se_sys_ioctl+0x9b/0xc0
__x64_sys_ioctl+0x19/0x30
x64_sys_call+0x2c4a/0x4620
do_syscall_64+0x9e/0x1b0
The issue can be triggered as below:
T1 T2
dm_suspend table_load
__dm_suspend dm_setup_md_queue
dm_mq_init_request_queue
blk_mq_init_allocated_queue
=> q->mq_ops = set->ops; (1)
dm_stop_queue / dm_wait_for_completion
=> q->tag_set NULL pointer! (2)
=> q->tag_set = set; (3)
Fix this by checking if a valid table (map) exists before performing
request-based suspend and waiting for target I/O. When map is NULL,
skip these table-dependent suspend steps.
Even when map is NULL, no I/O can reach any target because there is
no table loaded; I/O submitted in this state will fail early in the
DM layer. Skipping the table-dependent suspend logic in this case
is safe and avoids NULL pointer dereferences. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: Fix peer lookup in ath12k_dp_mon_rx_deliver_msdu()
In ath12k_dp_mon_rx_deliver_msdu(), peer lookup fails because
rxcb->peer_id is not updated with a valid value. This is expected
in monitor mode, where RX frames bypass the regular RX
descriptor path that typically sets rxcb->peer_id.
As a result, the peer is NULL, and link_id and link_valid fields
in the RX status are not populated. This leads to a WARN_ON in
mac80211 when it receives data frame from an associated station
with invalid link_id.
Fix this potential issue by using ppduinfo->peer_id, which holds
the correct peer id for the received frame. This ensures that the
peer is correctly found and the associated link metadata is updated
accordingly.
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1 |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: Intel: sof_sdw: Prevent jump to NULL add_sidecar callback
In create_sdw_dailink() check that sof_end->codec_info->add_sidecar
is not NULL before calling it.
The original code assumed that if include_sidecar is true, the codec
on that link has an add_sidecar callback. But there could be other
codecs on the same link that do not have an add_sidecar callback. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency()
syzbot reported a f2fs bug as below:
Oops: gen[ 107.736417][ T5848] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5848 Comm: syz-executor263 Tainted: G W 6.17.0-rc1-syzkaller-00014-g0e39a731820a #0 PREEMPT_{RT,(full)}
RIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284
Call Trace:
<TASK>
f2fs_check_quota_consistency fs/f2fs/super.c:1188 [inline]
f2fs_check_opt_consistency+0x1378/0x2c10 fs/f2fs/super.c:1436
__f2fs_remount fs/f2fs/super.c:2653 [inline]
f2fs_reconfigure+0x482/0x1770 fs/f2fs/super.c:5297
reconfigure_super+0x224/0x890 fs/super.c:1077
do_remount fs/namespace.c:3314 [inline]
path_mount+0xd18/0xfe0 fs/namespace.c:4112
do_mount fs/namespace.c:4133 [inline]
__do_sys_mount fs/namespace.c:4344 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4321
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The direct reason is f2fs_check_quota_consistency() may suffer null-ptr-deref
issue in strcmp().
The bug can be reproduced w/ below scripts:
mkfs.f2fs -f /dev/vdb
mount -t f2fs -o usrquota /dev/vdb /mnt/f2fs
quotacheck -uc /mnt/f2fs/
umount /mnt/f2fs
mount -t f2fs -o usrjquota=aquota.user,jqfmt=vfsold /dev/vdb /mnt/f2fs
mount -t f2fs -o remount,usrjquota=,jqfmt=vfsold /dev/vdb /mnt/f2fs
umount /mnt/f2fs
So, before old_qname and new_qname comparison, we need to check whether
they are all valid pointers, fix it. |
| In the Linux kernel, the following vulnerability has been resolved:
PCI/pwrctrl: Fix double cleanup on devm_add_action_or_reset() failure
When devm_add_action_or_reset() fails, it calls the passed cleanup
function. Hence the caller must not repeat that cleanup.
Replace the "goto err_regulator_free" by the actual freeing, as there
will never be a need again for a second user of this label. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/msm: Fix bootup splat with separate_gpu_drm modparam
The drm_gem_for_each_gpuvm_bo() call from lookup_vma() accesses
drm_gem_obj.gpuva.list, which is not initialized when the drm driver
does not support DRIVER_GEM_GPUVA feature. Enable it for msm_kms
drm driver to fix the splat seen when msm.separate_gpu_drm=1 modparam
is set:
[ 9.506020] Unable to handle kernel paging request at virtual address fffffffffffffff0
[ 9.523160] Mem abort info:
[ 9.523161] ESR = 0x0000000096000006
[ 9.523163] EC = 0x25: DABT (current EL), IL = 32 bits
[ 9.523165] SET = 0, FnV = 0
[ 9.523166] EA = 0, S1PTW = 0
[ 9.523167] FSC = 0x06: level 2 translation fault
[ 9.523169] Data abort info:
[ 9.523170] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
[ 9.523171] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 9.523172] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 9.523174] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000ad370f000
[ 9.523176] [fffffffffffffff0] pgd=0000000000000000, p4d=0000000ad4787403, pud=0000000ad4788403, pmd=0000000000000000
[ 9.523184] Internal error: Oops: 0000000096000006 [#1] SMP
[ 9.592968] CPU: 9 UID: 0 PID: 448 Comm: (udev-worker) Not tainted 6.17.0-rc4-assorted-fix-00005-g0e9bb53a2282-dirty #3 PREEMPT
[ 9.592970] Hardware name: Qualcomm CRD, BIOS 6.0.240718.BOOT.MXF.2.4-00515-HAMOA-1 07/18/2024
[ 9.592971] pstate: a1400005 (NzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 9.592973] pc : lookup_vma+0x28/0xe0 [msm]
[ 9.592996] lr : get_vma_locked+0x2c/0x128 [msm]
[ 9.763632] sp : ffff800082dab460
[ 9.763666] Call trace:
[ 9.763668] lookup_vma+0x28/0xe0 [msm] (P)
[ 9.763688] get_vma_locked+0x2c/0x128 [msm]
[ 9.763706] msm_gem_get_and_pin_iova_range+0x68/0x11c [msm]
[ 9.763723] msm_gem_get_and_pin_iova+0x18/0x24 [msm]
[ 9.763740] msm_fbdev_driver_fbdev_probe+0xd0/0x258 [msm]
[ 9.763760] __drm_fb_helper_initial_config_and_unlock+0x288/0x528 [drm_kms_helper]
[ 9.763771] drm_fb_helper_initial_config+0x44/0x54 [drm_kms_helper]
[ 9.763779] drm_fbdev_client_hotplug+0x84/0xd4 [drm_client_lib]
[ 9.763782] drm_client_register+0x58/0x9c [drm]
[ 9.763806] drm_fbdev_client_setup+0xe8/0xcf0 [drm_client_lib]
[ 9.763809] drm_client_setup+0xb4/0xd8 [drm_client_lib]
[ 9.763811] msm_drm_kms_post_init+0x2c/0x3c [msm]
[ 9.763830] msm_drm_init+0x1a8/0x22c [msm]
[ 9.763848] msm_drm_bind+0x30/0x3c [msm]
[ 9.919273] try_to_bring_up_aggregate_device+0x168/0x1d4
[ 9.919283] __component_add+0xa4/0x170
[ 9.919286] component_add+0x14/0x20
[ 9.919288] msm_dp_display_probe_tail+0x4c/0xac [msm]
[ 9.919315] msm_dp_auxbus_done_probe+0x14/0x20 [msm]
[ 9.919335] dp_aux_ep_probe+0x4c/0xf0 [drm_dp_aux_bus]
[ 9.919341] really_probe+0xbc/0x298
[ 9.919345] __driver_probe_device+0x78/0x12c
[ 9.919348] driver_probe_device+0x40/0x160
[ 9.919350] __driver_attach+0x94/0x19c
[ 9.919353] bus_for_each_dev+0x74/0xd4
[ 9.919355] driver_attach+0x24/0x30
[ 9.919358] bus_add_driver+0xe4/0x208
[ 9.919360] driver_register+0x60/0x128
[ 9.919363] __dp_aux_dp_driver_register+0x24/0x30 [drm_dp_aux_bus]
[ 9.919365] atana33xc20_init+0x20/0x1000 [panel_samsung_atna33xc20]
[ 9.919370] do_one_initcall+0x6c/0x1b0
[ 9.919374] do_init_module+0x58/0x234
[ 9.919377] load_module+0x19cc/0x1bd4
[ 9.919380] init_module_from_file+0x84/0xc4
[ 9.919382] __arm64_sys_finit_module+0x1b8/0x2cc
[ 9.919384] invoke_syscall+0x48/0x110
[ 9.919389] el0_svc_common.constprop.0+0xc8/0xe8
[ 9.919393] do_el0_svc+0x20/0x2c
[ 9.919396] el0_svc+0x34/0xf0
[ 9.919401] el0t_64_sync_handler+0xa0/0xe4
[ 9.919403] el0t_64_sync+0x198/0x19c
[ 9.919407] Code: eb0000bf 54000480 d100a003 aa0303e2 (f8418c44)
[ 9.919410] ---[ end trace 0000000000000000 ]---
Patchwork: https://patchwork.freedesktop.org/pa
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: amd/sdw_utils: avoid NULL deref when devm_kasprintf() fails
devm_kasprintf() may return NULL on memory allocation failure,
but the debug message prints cpus->dai_name before checking it.
Move the dev_dbg() call after the NULL check to prevent potential
NULL pointer dereference. |
| In the Linux kernel, the following vulnerability has been resolved:
idpf: cleanup remaining SKBs in PTP flows
When the driver requests Tx timestamp value, one of the first steps is
to clone SKB using skb_get. It increases the reference counter for that
SKB to prevent unexpected freeing by another component.
However, there may be a case where the index is requested, SKB is
assigned and never consumed by PTP flows - for example due to reset during
running PTP apps.
Add a check in release timestamping function to verify if the SKB
assigned to Tx timestamp latch was freed, and release remaining SKBs. |
| In the Linux kernel, the following vulnerability has been resolved:
pid: Add a judgment for ns null in pid_nr_ns
__task_pid_nr_ns
ns = task_active_pid_ns(current);
pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
if (pid && ns->level <= pid->level) {
Sometimes null is returned for task_active_pid_ns. Then it will trigger kernel panic in pid_nr_ns.
For example:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058
Mem abort info:
ESR = 0x0000000096000007
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x07: level 3 translation fault
Data abort info:
ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 39-bit VAs, pgdp=00000002175aa000
[0000000000000058] pgd=08000002175ab003, p4d=08000002175ab003, pud=08000002175ab003, pmd=08000002175be003, pte=0000000000000000
pstate: 834000c5 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __task_pid_nr_ns+0x74/0xd0
lr : __task_pid_nr_ns+0x24/0xd0
sp : ffffffc08001bd10
x29: ffffffc08001bd10 x28: ffffffd4422b2000 x27: 0000000000000001
x26: ffffffd442821168 x25: ffffffd442821000 x24: 00000f89492eab31
x23: 00000000000000c0 x22: ffffff806f5693c0 x21: ffffff806f5693c0
x20: 0000000000000001 x19: 0000000000000000 x18: 0000000000000000
x17: 00000000529c6ef0 x16: 00000000529c6ef0 x15: 00000000023a1adc
x14: 0000000000000003 x13: 00000000007ef6d8 x12: 001167c391c78800
x11: 00ffffffffffffff x10: 0000000000000000 x9 : 0000000000000001
x8 : ffffff80816fa3c0 x7 : 0000000000000000 x6 : 49534d702d535449
x5 : ffffffc080c4c2c0 x4 : ffffffd43ee128c8 x3 : ffffffd43ee124dc
x2 : 0000000000000000 x1 : 0000000000000001 x0 : ffffff806f5693c0
Call trace:
__task_pid_nr_ns+0x74/0xd0
...
__handle_irq_event_percpu+0xd4/0x284
handle_irq_event+0x48/0xb0
handle_fasteoi_irq+0x160/0x2d8
generic_handle_domain_irq+0x44/0x60
gic_handle_irq+0x4c/0x114
call_on_irq_stack+0x3c/0x74
do_interrupt_handler+0x4c/0x84
el1_interrupt+0x34/0x58
el1h_64_irq_handler+0x18/0x24
el1h_64_irq+0x68/0x6c
account_kernel_stack+0x60/0x144
exit_task_stack_account+0x1c/0x80
do_exit+0x7e4/0xaf8
...
get_signal+0x7bc/0x8d8
do_notify_resume+0x128/0x828
el0_svc+0x6c/0x70
el0t_64_sync_handler+0x68/0xbc
el0t_64_sync+0x1a8/0x1ac
Code: 35fffe54 911a02a8 f9400108 b4000128 (b9405a69)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt |
| In the Linux kernel, the following vulnerability has been resolved:
accel/qaic: Fix bootlog initialization ordering
As soon as we queue MHI buffers to receive the bootlog from the device,
we could be receiving data. Therefore all the resources needed to
process that data need to be setup prior to queuing the buffers.
We currently initialize some of the resources after queuing the buffers
which creates a race between the probe() and any data that comes back
from the device. If the uninitialized resources are accessed, we could
see page faults.
Fix the init ordering to close the race. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/kvm: Force legacy PCI hole to UC when overriding MTRRs for TDX/SNP
When running as an SNP or TDX guest under KVM, force the legacy PCI hole,
i.e. memory between Top of Lower Usable DRAM and 4GiB, to be mapped as UC
via a forced variable MTRR range.
In most KVM-based setups, legacy devices such as the HPET and TPM are
enumerated via ACPI. ACPI enumeration includes a Memory32Fixed entry, and
optionally a SystemMemory descriptor for an OperationRegion, e.g. if the
device needs to be accessed via a Control Method.
If a SystemMemory entry is present, then the kernel's ACPI driver will
auto-ioremap the region so that it can be accessed at will. However, the
ACPI spec doesn't provide a way to enumerate the memory type of
SystemMemory regions, i.e. there's no way to tell software that a region
must be mapped as UC vs. WB, etc. As a result, Linux's ACPI driver always
maps SystemMemory regions using ioremap_cache(), i.e. as WB on x86.
The dedicated device drivers however, e.g. the HPET driver and TPM driver,
want to map their associated memory as UC or WC, as accessing PCI devices
using WB is unsupported.
On bare metal and non-CoCO, the conflicting requirements "work" as firmware
configures the PCI hole (and other device memory) to be UC in the MTRRs.
So even though the ACPI mappings request WB, they are forced to UC- in the
kernel's tracking due to the kernel properly handling the MTRR overrides,
and thus are compatible with the drivers' requested WC/UC-.
With force WB MTRRs on SNP and TDX guests, the ACPI mappings get their
requested WB if the ACPI mappings are established before the dedicated
driver code attempts to initialize the device. E.g. if acpi_init()
runs before the corresponding device driver is probed, ACPI's WB mapping
will "win", and result in the driver's ioremap() failing because the
existing WB mapping isn't compatible with the requested WC/UC-.
E.g. when a TPM is emulated by the hypervisor (ignoring the security
implications of relying on what is allegedly an untrusted entity to store
measurements), the TPM driver will request UC and fail:
[ 1.730459] ioremap error for 0xfed40000-0xfed45000, requested 0x2, got 0x0
[ 1.732780] tpm_tis MSFT0101:00: probe with driver tpm_tis failed with error -12
Note, the '0x2' and '0x0' values refer to "enum page_cache_mode", not x86's
memtypes (which frustratingly are an almost pure inversion; 2 == WB, 0 == UC).
E.g. tracing mapping requests for TPM TIS yields:
Mapping TPM TIS with req_type = 0
WARNING: CPU: 22 PID: 1 at arch/x86/mm/pat/memtype.c:530 memtype_reserve+0x2ab/0x460
Modules linked in:
CPU: 22 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.16.0-rc7+ #2 VOLUNTARY
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/29/2025
RIP: 0010:memtype_reserve+0x2ab/0x460
__ioremap_caller+0x16d/0x3d0
ioremap_cache+0x17/0x30
x86_acpi_os_ioremap+0xe/0x20
acpi_os_map_iomem+0x1f3/0x240
acpi_os_map_memory+0xe/0x20
acpi_ex_system_memory_space_handler+0x273/0x440
acpi_ev_address_space_dispatch+0x176/0x4c0
acpi_ex_access_region+0x2ad/0x530
acpi_ex_field_datum_io+0xa2/0x4f0
acpi_ex_extract_from_field+0x296/0x3e0
acpi_ex_read_data_from_field+0xd1/0x460
acpi_ex_resolve_node_to_value+0x2ee/0x530
acpi_ex_resolve_to_value+0x1f2/0x540
acpi_ds_evaluate_name_path+0x11b/0x190
acpi_ds_exec_end_op+0x456/0x960
acpi_ps_parse_loop+0x27a/0xa50
acpi_ps_parse_aml+0x226/0x600
acpi_ps_execute_method+0x172/0x3e0
acpi_ns_evaluate+0x175/0x5f0
acpi_evaluate_object+0x213/0x490
acpi_evaluate_integer+0x6d/0x140
acpi_bus_get_status+0x93/0x150
acpi_add_single_object+0x43a/0x7c0
acpi_bus_check_add+0x149/0x3a0
acpi_bus_check_add_1+0x16/0x30
acpi_ns_walk_namespace+0x22c/0x360
acpi_walk_namespace+0x15c/0x170
acpi_bus_scan+0x1dd/0x200
acpi_scan_init+0xe5/0x2b0
acpi_init+0x264/0x5b0
do_one_i
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
pwm: berlin: Fix wrong register in suspend/resume
The 'enable' register should be BERLIN_PWM_EN rather than
BERLIN_PWM_ENABLE, otherwise, the driver accesses wrong address, there
will be cpu exception then kernel panic during suspend/resume. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix kfd process ref leaking when userptr unmapping
kfd_lookup_process_by_pid hold the kfd process reference to ensure it
doesn't get destroyed while sending the segfault event to user space.
Calling kfd_lookup_process_by_pid as function parameter leaks the kfd
process refcount and miss the NULL pointer check if app process is
already destroyed. |
| In the Linux kernel, the following vulnerability has been resolved:
xtensa: simdisk: add input size check in proc_write_simdisk
A malicious user could pass an arbitrarily bad value
to memdup_user_nul(), potentially causing kernel crash.
This follows the same pattern as commit ee76746387f6
("netdevsim: prevent bad user input in nsim_dev_health_break_write()") |
| In the Linux kernel, the following vulnerability has been resolved:
mount: handle NULL values in mnt_ns_release()
When calling in listmount() mnt_ns_release() may be passed a NULL
pointer. Handle that case gracefully. |
| In the Linux kernel, the following vulnerability has been resolved:
media: mc: Clear minor number before put device
The device minor should not be cleared after the device is released. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs: dealloc commit test ctx always
The damon_ctx for testing online DAMON parameters commit inputs is
deallocated only when the test fails. This means memory is leaked for
every successful online DAMON parameters commit. Fix the leak by always
deallocating it. |
| In the Linux kernel, the following vulnerability has been resolved:
Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"
I've found that pynfs COMP6 now leaves the connection or lease in a
strange state, which causes CLOSE9 to hang indefinitely. I've dug
into it a little, but I haven't been able to root-cause it yet.
However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on
number of operations per NFSv4 COMPOUND").
Tianshuo Han also reports a potential vulnerability when decoding
an NFSv4 COMPOUND. An attacker can place an arbitrarily large op
count in the COMPOUND header, which results in:
[ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total
pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO),
nodemask=(null),cpuset=/,mems_allowed=0
when NFSD attempts to allocate the COMPOUND op array.
Let's restore the operation-per-COMPOUND limit, but increased to 200
for now. |
| In the Linux kernel, the following vulnerability has been resolved:
fuse: fix livelock in synchronous file put from fuseblk workers
I observed a hang when running generic/323 against a fuseblk server.
This test opens a file, initiates a lot of AIO writes to that file
descriptor, and closes the file descriptor before the writes complete.
Unsurprisingly, the AIO exerciser threads are mostly stuck waiting for
responses from the fuseblk server:
# cat /proc/372265/task/372313/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_do_getattr+0xfc/0x1f0 [fuse]
[<0>] fuse_file_read_iter+0xbe/0x1c0 [fuse]
[<0>] aio_read+0x130/0x1e0
[<0>] io_submit_one+0x542/0x860
[<0>] __x64_sys_io_submit+0x98/0x1a0
[<0>] do_syscall_64+0x37/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
But the /weird/ part is that the fuseblk server threads are waiting for
responses from itself:
# cat /proc/372210/task/372232/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_file_put+0x9a/0xd0 [fuse]
[<0>] fuse_release+0x36/0x50 [fuse]
[<0>] __fput+0xec/0x2b0
[<0>] task_work_run+0x55/0x90
[<0>] syscall_exit_to_user_mode+0xe9/0x100
[<0>] do_syscall_64+0x43/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
The fuseblk server is fuse2fs so there's nothing all that exciting in
the server itself. So why is the fuse server calling fuse_file_put?
The commit message for the fstest sheds some light on that:
"By closing the file descriptor before calling io_destroy, you pretty
much guarantee that the last put on the ioctx will be done in interrupt
context (during I/O completion).
Aha. AIO fgets a new struct file from the fd when it queues the ioctx.
The completion of the FUSE_WRITE command from userspace causes the fuse
server to call the AIO completion function. The completion puts the
struct file, queuing a delayed fput to the fuse server task. When the
fuse server task returns to userspace, it has to run the delayed fput,
which in the case of a fuseblk server, it does synchronously.
Sending the FUSE_RELEASE command sychronously from fuse server threads
is a bad idea because a client program can initiate enough simultaneous
AIOs such that all the fuse server threads end up in delayed_fput, and
now there aren't any threads left to handle the queued fuse commands.
Fix this by only using asynchronous fputs when closing files, and leave
a comment explaining why. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: prevent poison consumption when splitting THP
When performing memory error injection on a THP (Transparent Huge Page)
mapped to userspace on an x86 server, the kernel panics with the following
trace. The expected behavior is to terminate the affected process instead
of panicking the kernel, as the x86 Machine Check code can recover from an
in-userspace #MC.
mce: [Hardware Error]: CPU 0: Machine Check Exception: f Bank 3: bd80000000070134
mce: [Hardware Error]: RIP 10:<ffffffff8372f8bc> {memchr_inv+0x4c/0xf0}
mce: [Hardware Error]: TSC afff7bbff88a ADDR 1d301b000 MISC 80 PPIN 1e741e77539027db
mce: [Hardware Error]: PROCESSOR 0:d06d0 TIME 1758093249 SOCKET 0 APIC 0 microcode 80000320
mce: [Hardware Error]: Run the above through 'mcelog --ascii'
mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel
Kernel panic - not syncing: Fatal local machine check
The root cause of this panic is that handling a memory failure triggered
by an in-userspace #MC necessitates splitting the THP. The splitting
process employs a mechanism, implemented in
try_to_map_unused_to_zeropage(), which reads the pages in the THP to
identify zero-filled pages. However, reading the pages in the THP results
in a second in-kernel #MC, occurring before the initial memory_failure()
completes, ultimately leading to a kernel panic. See the kernel panic
call trace on the two #MCs.
First Machine Check occurs // [1]
memory_failure() // [2]
try_to_split_thp_page()
split_huge_page()
split_huge_page_to_list_to_order()
__folio_split() // [3]
remap_page()
remove_migration_ptes()
remove_migration_pte()
try_to_map_unused_to_zeropage() // [4]
memchr_inv() // [5]
Second Machine Check occurs // [6]
Kernel panic
[1] Triggered by accessing a hardware-poisoned THP in userspace, which is
typically recoverable by terminating the affected process.
[2] Call folio_set_has_hwpoisoned() before try_to_split_thp_page().
[3] Pass the RMP_USE_SHARED_ZEROPAGE remap flag to remap_page().
[4] Try to map the unused THP to zeropage.
[5] Re-access pages in the hw-poisoned THP in the kernel.
[6] Triggered in-kernel, leading to a panic kernel.
In Step[2], memory_failure() sets the poisoned flag on the page in the THP
by TestSetPageHWPoison() before calling try_to_split_thp_page().
As suggested by David Hildenbrand, fix this panic by not accessing to the
poisoned page in the THP during zeropage identification, while continuing
to scan unaffected pages in the THP for possible zeropage mapping. This
prevents a second in-kernel #MC that would cause kernel panic in Step[4].
Thanks to Andrew Zaborowski for his initial work on fixing this issue. |
