{"id":"DEBIAN-CVE-2026-98431","details":"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 -\u003e disassociation_lock    Thread B (disassociate):     disassociation_lock -\u003e 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-\u003emmap_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-\u003edisassociation_lock){+.+.}-{4:4}, at: uverbs_user_mmap_disassociate+0x39/0x780 [ib_uverbs]  [  776.663177]  [  776.663177] which lock already depends on the new lock.  [  776.663177]  [  776.664525]  [  776.664525] the existing dependency chain (in reverse order) is:  [  776.665724]  [  776.665724] -\u003e #2 (&file-\u003edisassociation_lock){+.+.}-{4:4}:  [  776.666887]        __mutex_lock+0x16d/0x2330  [  776.667633]        rdma_umap_open+0x129/0x280 [ib_uverbs]  [  776.668489]        dup_mmap+0xa40/0x1790  [  776.669170]        copy_process+0x5dd2/0x6170  [  776.669933]        kernel_clone+0xb6/0x610  [  776.670636]        __do_sys_clone+0xb5/0xf0  [  776.671354]        do_syscall_64+0x70/0x12e0  [  776.672083]        entry_SYSCALL_64_after_hwframe+0x4b/0x53  [  776.672940]  [  776.672940] -\u003e #1 (&mm-\u003emmap_lock/1){+.+.}-{4:4}:  [  776.673985]        down_write_nested+0x90/0x1e0  [  776.674751]        dup_mmap+0x201/0x1790  [  776.675448]        copy_process+0x5dd2/0x6170  [  776.676180]        kernel_clone+0xb6/0x610  [  776.676904]        __do_sys_clone+0xb5/0xf0  [  776.677615]        do_syscall_64+0x70/0x12e0  [  776.678351]        entry_SYSCALL_64_after_hwframe+0x4b/0x53  [  776.679239]  [  776.679239] -\u003e #0 (&mm-\u003emmap_lock){++++}-{4:4}:  [  776.680253]        __lock_acquire+0x18c6/0x2ec0  [  776.681018]        lock_acquire+0x10e/0x2e0  [  776.681742]        down_read+0x95/0x430  [  776.682395]        uverbs_user_mmap_disassociate+0x168/0x780 [ib_uverbs]  [  776.683436]        uverbs_destroy_ufile_hw+0x1ae/0x270 [ib_uverbs]  [  776.684416]        ib_uverbs_remove_one+0x22b/0x420 [ib_uverbs]  [  776.685371]        remove_client_context+0xa6/0xf0 [ib_core]  [  776.686342]        disable_device+0x12b/0x240 [ib_core]  [  776.687249]        __ib_unregister_device+0x269/0x460 [ib_core]  [  776.688233]        ib_unregister_device+0x21/0x30 [ib_core]  [  776.689140]        mlx5r_remove+0xd0/0x170 [mlx5_ib]  [  776.689999]        device_release_driver_internal+0x3b2/0x5 ---truncated---","modified":"2026-10-15T05:01:43.699358447Z","published":"2026-10-14T14:17:54.887Z","upstream":["CVE-2026-98431"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-98431"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.111-1","6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.10-1","6.17.11-1","6.17.12-1","6.17.13-1","6.17.13-1~bpo13+1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1","6.18.1-1~exp1","6.18.10-1","6.18.12-1","6.18.12-1~bpo13+1","6.18.13-1","6.18.14-1","6.18.15-1","6.18.15-1~bpo13+1","6.18.2-1~exp1","6.18.3-1","6.18.5-1","6.18.5-1~bpo13+1","6.18.8-1","6.18.9-1","6.18.9-1~bpo13+1","6.18~rc4-1~exp1","6.18~rc4-1~exp2","6.18~rc5-1~exp1","6.18~rc6-1~exp1","6.18~rc7-1~exp1","6.19-1~exp1","6.19.10-1","6.19.10-1~bpo13+1","6.19.11-1","6.19.11-1~bpo13+1","6.19.12-1","6.19.13-1","6.19.13-1~bpo13+1","6.19.14-1","6.19.14-1~bpo13+1","6.19.2-1~exp1","6.19.3-1~exp1","6.19.4-1~exp1","6.19.5-1~exp1","6.19.6-1","6.19.6-2","6.19.6-2~bpo13+1","6.19.8-1","6.19.8-1~bpo13+1","6.19~rc4-1~exp1","6.19~rc5-1~exp1","6.19~rc6-1~exp1","6.19~rc7-1~exp1","6.19~rc8-1~exp1","7.0-1~exp1","7.0.1-1~exp1","7.0.10-1","7.0.10-1~bpo13+1","7.0.12-1","7.0.12-2","7.0.12-2~bpo13+1","7.0.13-1","7.0.13-1~bpo13+1","7.0.14-1","7.0.3-1","7.0.4-1","7.0.4-1~bpo13+1","7.0.7-1","7.0.7-1~bpo13+1","7.0.9-1","7.0.9-1~bpo13+1","7.1.1-1~exp1","7.1.10-1","7.1.12-1","7.1.13-1","7.1.13-1~bpo13+1","7.1.2-1~exp1","7.1.3-1","7.1.3-1+sunvdc","7.1.3-1~bpo13+1","7.1.4-1","7.1.5-1","7.1.6-1","7.1.7-1","7.1.7-1~bpo13+1","7.1.8-1","7.1.8-1~bpo13+1","7.1.8-2","7.1.9-1","7.1.9-1+sparc64","7.1~rc2-1~exp1","7.1~rc3-1~exp1","7.1~rc4-1~exp1","7.1~rc4-1~exp2","7.1~rc5-1~exp1","7.1~rc7-1~exp1","7.2.10-1","7.2.2-1~exp1","7.2.3-1~exp1","7.2.6-1","7.2.6-1~bpo13+1","7.2.7-1","7.2.8-1","7.2.9-1","7.2~rc3-1~exp1","7.2~rc5-1~exp1","7.2~rc7-1~exp1","7.3~rc6-1~exp1"],"ecosystem_specific":{"urgency":"not 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