| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-57896: btrfs: flush delalloc workers queue before stopping cleaner kthread during unmount |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: flush delalloc workers queue before stopping cleaner kthread during unmount |
| |
| During the unmount path, at close_ctree(), we first stop the cleaner |
| kthread, using kthread_stop() which frees the associated task_struct, and |
| then stop and destroy all the work queues. However after we stopped the |
| cleaner we may still have a worker from the delalloc_workers queue running |
| inode.c:submit_compressed_extents(), which calls btrfs_add_delayed_iput(), |
| which in turn tries to wake up the cleaner kthread - which was already |
| destroyed before, resulting in a use-after-free on the task_struct. |
| |
| Syzbot reported this with the following stack traces: |
| |
| BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089 |
| Read of size 8 at addr ffff8880259d2818 by task kworker/u8:3/52 |
| |
| CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 |
| Workqueue: btrfs-delalloc btrfs_work_helper |
| Call Trace: |
| <TASK> |
| __dump_stack lib/dump_stack.c:94 [inline] |
| dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 |
| print_address_description mm/kasan/report.c:378 [inline] |
| print_report+0x169/0x550 mm/kasan/report.c:489 |
| kasan_report+0x143/0x180 mm/kasan/report.c:602 |
| __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089 |
| lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 |
| __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] |
| _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 |
| class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] |
| try_to_wake_up+0xc2/0x1470 kernel/sched/core.c:4205 |
| submit_compressed_extents+0xdf/0x16e0 fs/btrfs/inode.c:1615 |
| run_ordered_work fs/btrfs/async-thread.c:288 [inline] |
| btrfs_work_helper+0x96f/0xc40 fs/btrfs/async-thread.c:324 |
| process_one_work kernel/workqueue.c:3229 [inline] |
| process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 |
| worker_thread+0x870/0xd30 kernel/workqueue.c:3391 |
| kthread+0x2f0/0x390 kernel/kthread.c:389 |
| ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 |
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 |
| </TASK> |
| |
| Allocated by task 2: |
| kasan_save_stack mm/kasan/common.c:47 [inline] |
| kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 |
| unpoison_slab_object mm/kasan/common.c:319 [inline] |
| __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345 |
| kasan_slab_alloc include/linux/kasan.h:250 [inline] |
| slab_post_alloc_hook mm/slub.c:4104 [inline] |
| slab_alloc_node mm/slub.c:4153 [inline] |
| kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4205 |
| alloc_task_struct_node kernel/fork.c:180 [inline] |
| dup_task_struct+0x57/0x8c0 kernel/fork.c:1113 |
| copy_process+0x5d1/0x3d50 kernel/fork.c:2225 |
| kernel_clone+0x223/0x870 kernel/fork.c:2807 |
| kernel_thread+0x1bc/0x240 kernel/fork.c:2869 |
| create_kthread kernel/kthread.c:412 [inline] |
| kthreadd+0x60d/0x810 kernel/kthread.c:767 |
| ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 |
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 |
| |
| Freed by task 24: |
| kasan_save_stack mm/kasan/common.c:47 [inline] |
| kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 |
| kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 |
| poison_slab_object mm/kasan/common.c:247 [inline] |
| __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 |
| kasan_slab_free include/linux/kasan.h:233 [inline] |
| slab_free_hook mm/slub.c:2338 [inline] |
| slab_free mm/slub.c:4598 [inline] |
| kmem_cache_free+0x195/0x410 mm/slub.c:4700 |
| put_task_struct include/linux/sched/task.h:144 [inline] |
| delayed_put_task_struct+0x125/0x300 kernel/exit.c:227 |
| rcu_do_batch kernel/rcu/tree.c:2567 [inline] |
| rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823 |
| handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:554 |
| run_ksoftirqd+0xca/0x130 kernel/softirq.c:943 |
| smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 |
| kthread+0x2f0/0x390 kernel/kthread.c:389 |
| ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 |
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 |
| |
| Last potentially related work creation: |
| kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 |
| __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544 |
| __call_rcu_common kernel/rcu/tree.c:3086 [inline] |
| call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190 |
| context_switch kernel/sched/core.c:5372 [inline] |
| __schedule+0x1803/0x4be0 kernel/sched/core.c:6756 |
| __schedule_loop kernel/sched/core.c:6833 [inline] |
| schedule+0x14b/0x320 kernel/sched/core.c:6848 |
| schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75 |
| do_wait_for_common kernel/sched/completion.c:95 [inline] |
| __wait_for_common kernel/sched/completion.c:116 [inline] |
| wait_for_common kernel/sched/completion.c:127 [inline] |
| wait_for_completion+0x355/0x620 kernel/sched/completion.c:148 |
| kthread_stop+0x19e/0x640 kernel/kthread.c:712 |
| close_ctree+0x524/0xd60 fs/btrfs/disk-io.c:4328 |
| generic_shutdown_super+0x139/0x2d0 fs/super.c:642 |
| kill_anon_super+0x3b/0x70 fs/super.c:1237 |
| btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2112 |
| deactivate_locked_super+0xc4/0x130 fs/super.c:473 |
| cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373 |
| task_work_run+0x24f/0x310 kernel/task_work.c:239 |
| ptrace_notify+0x2d2/0x380 kernel/signal.c:2503 |
| ptrace_report_syscall include/linux/ptrace.h:415 [inline] |
| ptrace_report_syscall_exit include/linux/ptrace.h:477 [inline] |
| syscall_exit_work+0xc7/0x1d0 kernel/entry/common.c:173 |
| syscall_exit_to_user_mode_prepare kernel/entry/common.c:200 [inline] |
| __syscall_exit_to_user_mode_work kernel/entry/common.c:205 [inline] |
| syscall_exit_to_user_mode+0x24a/0x340 kernel/entry/common.c:218 |
| do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 |
| entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| |
| The buggy address belongs to the object at ffff8880259d1e00 |
| which belongs to the cache task_struct of size 7424 |
| The buggy address is located 2584 bytes inside of |
| freed 7424-byte region [ffff8880259d1e00, ffff8880259d3b00) |
| |
| The buggy address belongs to the physical page: |
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x259d0 |
| head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 |
| memcg:ffff88802f4b56c1 |
| flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) |
| page_type: f5(slab) |
| raw: 00fff00000000040 ffff88801bafe500 dead000000000100 dead000000000122 |
| raw: 0000000000000000 0000000000040004 00000001f5000000 ffff88802f4b56c1 |
| head: 00fff00000000040 ffff88801bafe500 dead000000000100 dead000000000122 |
| head: 0000000000000000 0000000000040004 00000001f5000000 ffff88802f4b56c1 |
| head: 00fff00000000003 ffffea0000967401 ffffffffffffffff 0000000000000000 |
| head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| page_owner tracks the page as allocated |
| page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12, tgid 12 (kworker/u8:1), ts 7328037942, free_ts 0 |
| set_page_owner include/linux/page_owner.h:32 [inline] |
| post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556 |
| prep_new_page mm/page_alloc.c:1564 [inline] |
| get_page_from_freelist+0x3651/0x37a0 mm/page_alloc.c:3474 |
| __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751 |
| alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 |
| alloc_slab_page+0x6a/0x140 mm/slub.c:2408 |
| allocate_slab+0x5a/0x2f0 mm/slub.c:2574 |
| new_slab mm/slub.c:2627 [inline] |
| ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815 |
| __slab_alloc+0x58/0xa0 mm/slub.c:3905 |
| __slab_alloc_node mm/slub.c:3980 [inline] |
| slab_alloc_node mm/slub.c:4141 [inline] |
| kmem_cache_alloc_node_noprof+0x269/0x380 mm/slub.c:4205 |
| alloc_task_struct_node kernel/fork.c:180 [inline] |
| dup_task_struct+0x57/0x8c0 kernel/fork.c:1113 |
| copy_process+0x5d1/0x3d50 kernel/fork.c:2225 |
| kernel_clone+0x223/0x870 kernel/fork.c:2807 |
| user_mode_thread+0x132/0x1a0 kernel/fork.c:2885 |
| call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171 |
| process_one_work kernel/workqueue.c:3229 [inline] |
| process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 |
| worker_thread+0x870/0xd30 kernel/workqueue.c:3391 |
| page_owner free stack trace missing |
| |
| Memory state around the buggy address: |
| ffff8880259d2700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff8880259d2780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| >ffff8880259d2800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ^ |
| ffff8880259d2880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff8880259d2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ================================================================== |
| |
| Fix this by flushing the delalloc workers queue before stopping the |
| cleaner kthread. |
| |
| The Linux kernel CVE team has assigned CVE-2024-57896 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.10.233 with commit a2718ed1eb8c3611b63f8933c7e68c8821fe2808 |
| Fixed in 5.15.176 with commit 63f4b594a688bf922e8691f0784679aa7af7988c |
| Fixed in 6.1.124 with commit 1ea629e7bb2fb40555e5e01a1b5095df31287017 |
| Fixed in 6.6.70 with commit 35916b2f96505a18dc7242a115611b718d9de725 |
| Fixed in 6.12.9 with commit d77a3a99b53d12c061c007cdc96df38825dee476 |
| Fixed in 6.13 with commit f10bef73fb355e3fc85e63a50386798be68ff486 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-57896 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| fs/btrfs/disk-io.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/a2718ed1eb8c3611b63f8933c7e68c8821fe2808 |
| https://git.kernel.org/stable/c/63f4b594a688bf922e8691f0784679aa7af7988c |
| https://git.kernel.org/stable/c/1ea629e7bb2fb40555e5e01a1b5095df31287017 |
| https://git.kernel.org/stable/c/35916b2f96505a18dc7242a115611b718d9de725 |
| https://git.kernel.org/stable/c/d77a3a99b53d12c061c007cdc96df38825dee476 |
| https://git.kernel.org/stable/c/f10bef73fb355e3fc85e63a50386798be68ff486 |
