CVSS
Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)
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Описание
Оригинално описание
In the Linux kernel, the following vulnerability has been resolved: RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency Commit 51976c6cd786 ("RDMA/core: Provide rdma_user_mmap_disassociate() to disassociate mmap pages") introduced disassociation_lock to protect new mmap registrations against uverbs_user_mmap_disassociate(), but created an ABBA deadlock: Thread A (mmap / fork): mmap_lock -> disassociation_lock Thread B (disassociate): disassociation_lock -> mmap_lock Fix by removing disassociation_lock entirely and using the pre-existing hw_destroy_rwsem instead. hw_destroy_rwsem already provides the same protection: rdma_umap_open() and ib_uverbs_mmap() both use down_read_trylock() before registering a new VMA, so holding hw_destroy_rwsem in uverbs_user_mmap_disassociate() is sufficient to block new registrations. trylock is used in both mmap paths (not blocking down_read) because mmap_lock is already held on entry, and uverbs_user_mmap_disassociate() acquires mmap_lock internally — a blocking read would recreate the same deadlock. The only caller that was not taking hw_destroy_rwsem for write was rdma_user_mmap_disassociate(). Fix it to take the rwsem per-ufile while iterating under lists_mutex. This is safe because ib_uverbs_close() releases hw_destroy_rwsem entirely before acquiring lists_mutex, so the two locks are never held simultaneously. lockdep warning: [ 776.654252] ====================================================== [ 776.655214] WARNING: possible circular locking dependency detected [ 776.656167] 6.18.0for-upstream_debug_94e244d9ccab #1 Not tainted [ 776.657114] ------------------------------------------------------ [ 776.658087] devlink/14824 is trying to acquire lock: [ 776.658879] ffff88811170c800 (&mm->mmap_lock){++++}-{4:4}, at: uverbs_user_mmap_disassociate+0x168/0x780 [ib_uverbs] [ 776.660479] [ 776.660479] but task is already holding lock: [ 776.661460] ffff888142d92b08 (&file->disassociati
Засегнати продукти
- Linux Linux: 51976c6cd786151b6a1bdf8b8b3334beac0ba99c преди 426f54f20b79c5b164a0472ad3f6ba36afcd08c6; 51976c6cd786151b6a1bdf8b8b3334beac0ba99c преди a44a3f175eaee7e5aeb6a8fed381c4a0d5f49236; 0598914a950ddfa694f410e482453cdbb9265515; 86092a4e46d161d24f8106df082e24b8efe87382; 6.11.11 преди 6.12; 6.12.2 преди 6.13
- Linux Linux: 6.13; преди 6.13; 7.2.8 до 7.2.*; 7.3 до *
История
- 14 октомври 2026 Публикувано