CVE-2024-35929: rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()
First published: Sun May 19 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/linux | <=5.10.223-1<=5.10.226-1<=6.1.106-3<=6.1.112-1 | 6.10.11-1 6.11.2-1 |
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Reference Links
- https://git.kernel.org/stable/c/4d58c9fb45c70e62c19e8be3f3605889c47601bc
- https://git.kernel.org/stable/c/927d1f4f77e4784ab3944a9df86ab14d1cd3185a
- https://git.kernel.org/stable/c/dda98810b552fc6bf650f4270edeebdc2f28bd3f
- https://launchpad.net/bugs/cve/CVE-2024-35929
- https://git.kernel.org/linus/dda98810b552fc6bf650f4270edeebdc2f28bd3f
- https://security-tracker.debian.org/tracker/CVE-2024-35929
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-35929
- https://nvd.nist.gov/vuln/detail/CVE-2024-35929
- https://ubuntu.com/security/CVE-2024-35929
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