cbcvebase.
CVE-2024-50140
published 2024-11-07

CVE-2024-50140: In the Linux kernel, the following vulnerability has been resolved: sched/core: Disable page allocation in task_tick_mm_cid() With KASAN and PREEMPT_RT…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.23%
13.9th percentile
In the Linux kernel, the following vulnerability has been resolved: sched/core: Disable page allocation in task_tick_mm_cid() With KASAN and PREEMPT_RT enabled, calling task_work_add() in task_tick_mm_cid() may cause the following splat. [ 63.696416] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 [ 63.696416] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 610, name: modprobe [ 63.696416] preempt_count: 10001, expected: 0 [ 63.696416] RCU nest depth: 1, expected: 1 This problem is caused by the following call trace. sched_tick() [ acquire rq->__lock ] -> task_tick_mm_cid() -> task_work_add() -> __kasan_record_aux_stack() -> kasan_save_stack() -> stack_depot_save_flags() -> alloc_pages_mpol_noprof() -> __alloc_pages_noprof() -> get_page_from_freelist() -> rmqueue() -> rmqueue_pcplist() -> __rmqueue_pcplist() -> rmqueue_bulk() -> rt_spin_lock() The rq lock is a raw_spinlock_t. We can't sleep while holding it. IOW, we can't call alloc_pages() in stack_depot_save_flags(). The task_tick_mm_cid() function with its task_work_add() call was introduced by commit 223baf9d17f2 ("sched: Fix performance regression introduced by mm_cid") in v6.4 kernel. Fortunately, there is a kasan_record_aux_stack_noalloc() variant that calls stack_depot_save_flags() while not allowing it to allocate new pages. To allow task_tick_mm_cid() to use task_work without page allocation, a new TWAF_NO_ALLOC flag is added to enable calling kasan_record_aux_stack_noalloc() instead of kasan_record_aux_stack() if set. The task_tick_mm_cid() function is modified to add this new flag. The possible downside is the missing stack trace in a KASAN report due to new page allocation required when task_work_add_noallloc() is called which should be rare.

Affected

14 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.11.6-1 (forky)linux 6.11.6-1 (forky)
linuxlinux
linuxlinux>= 223baf9d17f25e2608dbdff7232c095c1e612268 < 509c29d0d26f68a6f6d0a05cb1a89725237e2b87509c29d0d26f68a6f6d0a05cb1a89725237e2b87
linuxlinux>= 223baf9d17f25e2608dbdff7232c095c1e612268 < ce0241ef83eed55f675376e8a3605d23de53d875ce0241ef83eed55f675376e8a3605d23de53d875
linuxlinux>= 223baf9d17f25e2608dbdff7232c095c1e612268 < 73ab05aa46b02d96509cb029a8d04fca7bbde8c773ab05aa46b02d96509cb029a8d04fca7bbde8c7
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.11.6-16.11.6-1
linuxlinux_kernel>= 0 < 6.11.6-16.11.6-1
linuxlinux_kernel>= 0 < 6.8.0-58.606.8.0-58.60
linuxlinux_kernel>= 0 < 6.11.0-18.186.11.0-18.18
linuxlinux_kernel>= 6.4 < 6.6.596.6.59
linuxlinux_kernel>= 6.7 < 6.11.66.11.6
msrcazl3_kernel_6.6.57.1-7_on_azure_linux_3.0
msrcazl3_kernel_6.6.64.2-1_on_azure_linux_3.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian5.5LOW
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
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