UBUNTU-CVE-2024-35929
In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock() For the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and CONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE() in the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions: CPU2 CPU11 kthread rcu_nocb_cb_kthread ksys_write rcu_do_batch vfs_write rcu_torture_timer_cb proc_sys_write __kmem_cache_free proc_sys_call_handler kmemleak_free drop_caches_sysctl_handler delete_object_full drop_slab __delete_object shrink_slab put_object lazy_rcu_shrink_scan call_rcu rcu_nocb_flush_bypass __call_rcu_commn rcu_nocb_bypass_lock raw_spin_trylock(&rdp->nocb_bypass_lock) fail atomic_inc(&rdp->nocb_lock_contended); rcu_nocb_wait_contended WARN_ON_ONCE(smp_processor_id() != rdp->cpu); WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)) | |_ _ _ _ _ _ _ _ _ _same rdp and rdp->cpu != 11_ _ _ _ _ _ _ _ _ __| Reproduce this bug with "echo 3 > /proc/sys/vm/drop_caches". This commit therefore uses rcu_nocb_try_flush_bypass() instead of rcu_nocb_flush_bypass() in lazy_rcu_shrink_scan(). If the nocb_bypass queue is being flushed, then rcu_nocb_try_flush_bypass will return directly.
02 / AFFECTED SOFTWARE
Affected packages
29 explicit affected versions
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45 explicit affected versions
1 explicit affected versions
37 explicit affected versions
6 explicit affected versions
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10 explicit affected versions
8 explicit affected versions
3 explicit affected versions
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38 explicit affected versions
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13 explicit affected versions
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10 explicit affected versions
13 explicit affected versions
1 explicit affected versions
10 explicit affected versions
10 explicit affected versions
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13 explicit affected versions
8 explicit affected versions
21 explicit affected versions
6 explicit affected versions
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12 explicit affected versions
7 explicit affected versions
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12 explicit affected versions
5 explicit affected versions
26 explicit affected versions
2 explicit affected versions
1 explicit affected versions
2 explicit affected versions
8 explicit affected versions
23 explicit affected versions
14 explicit affected versions
5 explicit affected versions
3 explicit affected versions
26 explicit affected versions
12 explicit affected versions
44 explicit affected versions
2 explicit affected versions
4 explicit affected versions
4 explicit affected versions
16 explicit affected versions
9 explicit affected versions
12 explicit affected versions
13 explicit affected versions
5 explicit affected versions
7 explicit affected versions
13 explicit affected versions
7 explicit affected versions
10 explicit affected versions
14 explicit affected versions
6 explicit affected versions
18 explicit affected versions
3 explicit affected versions
16 explicit affected versions
43 explicit affected versions
9 explicit affected versions
2 explicit affected versions
11 explicit affected versions
35 explicit affected versions
12 explicit affected versions
7 explicit affected versions
13 explicit affected versions
6 explicit affected versions
12 explicit affected versions
50 explicit affected versions
11 explicit affected versions
12 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock() For the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and CONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE() in the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions: CPU2 CPU11 kthread rcu_nocb_cb_kthread ksys_write rcu_do_batch vfs_write rcu_torture_timer_cb proc_sys_write __kmem_cache_free proc_sys_call_handler kmemleak_free drop_caches_sysctl_handler delete_object_full drop_slab __delete_object shrink_slab put_object lazy_rcu_shrink_scan call_rcu rcu_nocb_flush_bypass __call_rcu_commn rcu_nocb_bypass_lock raw_spin_trylock(&rdp->nocb_bypass_lock) fail atomic_inc(&rdp->nocb_lock_contended); rcu_nocb_wait_contended WARN_ON_ONCE(smp_processor_id() != rdp->cpu); WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)) | |_ _ _ _ _ _ _ _ _ _same rdp and rdp->cpu != 11_ _ _ _ _ _ _ _ _ __| Reproduce this bug with "echo 3 > /proc/sys/vm/drop_caches". This commit therefore uses rcu_nocb_try_flush_bypass() instead of rcu_nocb_flush_bypass() in lazy_rcu_shrink_scan(). If the nocb_bypass queue is being flushed, then rcu_nocb_try_flush_bypass will return directly.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/dda98810b552fc6bf650f4270edeebdc2f28bd3f
- https://git.kernel.org/stable/c/4d58c9fb45c70e62c19e8be3f3605889c47601bc
- https://git.kernel.org/stable/c/927d1f4f77e4784ab3944a9df86ab14d1cd3185a
- https://git.kernel.org/stable/c/dda98810b552fc6bf650f4270edeebdc2f28bd3f
- https://ubuntu.com/security/CVE-2024-35929
- https://ubuntu.com/security/notices/USN-6893-1
- https://ubuntu.com/security/notices/USN-6893-2
- https://ubuntu.com/security/notices/USN-6893-3
- https://ubuntu.com/security/notices/USN-6918-1
- https://www.cve.org/CVERecord?id=CVE-2024-35929