| 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-2024-49867: btrfs: wait for fixup workers before stopping cleaner kthread during umount |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: wait for fixup workers before stopping cleaner kthread during umount |
| |
| During unmount, at close_ctree(), we have the following steps in this order: |
| |
| 1) Park the cleaner kthread - this doesn't destroy the kthread, it basically |
| halts its execution (wake ups against it work but do nothing); |
| |
| 2) We stop the cleaner kthread - this results in freeing the respective |
| struct task_struct; |
| |
| 3) We call btrfs_stop_all_workers() which waits for any jobs running in all |
| the work queues and then free the work queues. |
| |
| Syzbot reported a case where a fixup worker resulted in a crash when doing |
| a delayed iput on its inode while attempting to wake up the cleaner at |
| btrfs_add_delayed_iput(), because the task_struct of the cleaner kthread |
| was already freed. This can happen during unmount because we don't wait |
| for any fixup workers still running before we call kthread_stop() against |
| the cleaner kthread, which stops and free all its resources. |
| |
| Fix this by waiting for any fixup workers at close_ctree() before we call |
| kthread_stop() against the cleaner and run pending delayed iputs. |
| |
| The stack traces reported by syzbot were the following: |
| |
| BUG: KASAN: slab-use-after-free in __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065 |
| Read of size 8 at addr ffff8880272a8a18 by task kworker/u8:3/52 |
| |
| CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.12.0-rc1-syzkaller #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 |
| Workqueue: btrfs-fixup 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:377 [inline] |
| print_report+0x169/0x550 mm/kasan/report.c:488 |
| kasan_report+0x143/0x180 mm/kasan/report.c:601 |
| __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065 |
| lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 |
| __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+0xb0/0x1480 kernel/sched/core.c:4154 |
| btrfs_writepage_fixup_worker+0xc16/0xdf0 fs/btrfs/inode.c:2842 |
| btrfs_work_helper+0x390/0xc50 fs/btrfs/async-thread.c:314 |
| process_one_work kernel/workqueue.c:3229 [inline] |
| process_scheduled_works+0xa63/0x1850 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:247 [inline] |
| slab_post_alloc_hook mm/slub.c:4086 [inline] |
| slab_alloc_node mm/slub.c:4135 [inline] |
| kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4187 |
| alloc_task_struct_node kernel/fork.c:180 [inline] |
| dup_task_struct+0x57/0x8c0 kernel/fork.c:1107 |
| copy_process+0x5d1/0x3d50 kernel/fork.c:2206 |
| kernel_clone+0x223/0x880 kernel/fork.c:2787 |
| kernel_thread+0x1bc/0x240 kernel/fork.c:2849 |
| create_kthread kernel/kthread.c:412 [inline] |
| kthreadd+0x60d/0x810 kernel/kthread.c:765 |
| 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 61: |
| 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:579 |
| 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:230 [inline] |
| slab_free_hook mm/slub.c:2343 [inline] |
| slab_free mm/slub.c:4580 [inline] |
| kmem_cache_free+0x1a2/0x420 mm/slub.c:4682 |
| put_task_struct include/linux/sched/task.h:144 [inline] |
| delayed_put_task_struct+0x125/0x300 kernel/exit.c:228 |
| rcu_do_batch kernel/rcu/tree.c:2567 [inline] |
| rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823 |
| handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 |
| __do_softirq kernel/softirq.c:588 [inline] |
| invoke_softirq kernel/softirq.c:428 [inline] |
| __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 |
| irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 |
| instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline] |
| sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037 |
| asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 |
| |
| 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:541 |
| __call_rcu_common kernel/rcu/tree.c:3086 [inline] |
| call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190 |
| context_switch kernel/sched/core.c:5318 [inline] |
| __schedule+0x184b/0x4ae0 kernel/sched/core.c:6675 |
| schedule_idle+0x56/0x90 kernel/sched/core.c:6793 |
| do_idle+0x56a/0x5d0 kernel/sched/idle.c:354 |
| cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424 |
| start_secondary+0x102/0x110 arch/x86/kernel/smpboot.c:314 |
| common_startup_64+0x13e/0x147 |
| |
| The buggy address belongs to the object at ffff8880272a8000 |
| which belongs to the cache task_struct of size 7424 |
| The buggy address is located 2584 bytes inside of |
| freed 7424-byte region [ffff8880272a8000, ffff8880272a9d00) |
| |
| The buggy address belongs to the physical page: |
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x272a8 |
| head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 |
| flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) |
| page_type: f5(slab) |
| raw: 00fff00000000040 ffff88801bafa500 dead000000000122 0000000000000000 |
| raw: 0000000000000000 0000000080040004 00000001f5000000 0000000000000000 |
| head: 00fff00000000040 ffff88801bafa500 dead000000000122 0000000000000000 |
| head: 0000000000000000 0000000080040004 00000001f5000000 0000000000000000 |
| head: 00fff00000000003 ffffea00009caa01 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 2, tgid 2 (kthreadd), ts 71247381401, free_ts 71214998153 |
| set_page_owner include/linux/page_owner.h:32 [inline] |
| post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537 |
| prep_new_page mm/page_alloc.c:1545 [inline] |
| get_page_from_freelist+0x3039/0x3180 mm/page_alloc.c:3457 |
| __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4733 |
| alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 |
| alloc_slab_page+0x6a/0x120 mm/slub.c:2413 |
| allocate_slab+0x5a/0x2f0 mm/slub.c:2579 |
| new_slab mm/slub.c:2632 [inline] |
| ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819 |
| __slab_alloc+0x58/0xa0 mm/slub.c:3909 |
| __slab_alloc_node mm/slub.c:3962 [inline] |
| slab_alloc_node mm/slub.c:4123 [inline] |
| kmem_cache_alloc_node_noprof+0x1fe/0x320 mm/slub.c:4187 |
| alloc_task_struct_node kernel/fork.c:180 [inline] |
| dup_task_struct+0x57/0x8c0 kernel/fork.c:1107 |
| copy_process+0x5d1/0x3d50 kernel/fork.c:2206 |
| kernel_clone+0x223/0x880 kernel/fork.c:2787 |
| kernel_thread+0x1bc/0x240 kernel/fork.c:2849 |
| create_kthread kernel/kthread.c:412 [inline] |
| kthreadd+0x60d/0x810 kernel/kthread.c:765 |
| ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 |
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 |
| page last free pid 5230 tgid 5230 stack trace: |
| reset_page_owner include/linux/page_owner.h:25 [inline] |
| free_pages_prepare mm/page_alloc.c:1108 [inline] |
| free_unref_page+0xcd0/0xf00 mm/page_alloc.c:2638 |
| discard_slab mm/slub.c:2678 [inline] |
| __put_partials+0xeb/0x130 mm/slub.c:3146 |
| put_cpu_partial+0x17c/0x250 mm/slub.c:3221 |
| __slab_free+0x2ea/0x3d0 mm/slub.c:4450 |
| qlink_free mm/kasan/quarantine.c:163 [inline] |
| qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 |
| kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 |
| __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 |
| kasan_slab_alloc include/linux/kasan.h:247 [inline] |
| slab_post_alloc_hook mm/slub.c:4086 [inline] |
| slab_alloc_node mm/slub.c:4135 [inline] |
| kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4142 |
| getname_flags+0xb7/0x540 fs/namei.c:139 |
| do_sys_openat2+0xd2/0x1d0 fs/open.c:1409 |
| do_sys_open fs/open.c:1430 [inline] |
| __do_sys_openat fs/open.c:1446 [inline] |
| __se_sys_openat fs/open.c:1441 [inline] |
| __x64_sys_openat+0x247/0x2a0 fs/open.c:1441 |
| do_syscall_x64 arch/x86/entry/common.c:52 [inline] |
| do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 |
| entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| |
| Memory state around the buggy address: |
| ffff8880272a8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff8880272a8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| >ffff8880272a8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ^ |
| ffff8880272a8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff8880272a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ================================================================== |
| |
| The Linux kernel CVE team has assigned CVE-2024-49867 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.19.323 with commit cd686dfff63f27d712877aef5b962fbf6b8bc264 |
| Fixed in 5.4.285 with commit a71349b692ab34ea197949e13e3cc42570fe73d9 |
| Fixed in 5.10.227 with commit 70b60c8d9b42763d6629e44f448aa5d8ae477d61 |
| Fixed in 5.15.168 with commit 4c98fe0dfa2ae83c4631699695506d8941db4bfe |
| Fixed in 6.1.113 with commit 9da40aea63f8769f28afb91aea0fac4cf6fbbb65 |
| Fixed in 6.6.55 with commit ed87190e9d9c80aad220fb6b0b03a84d22e2c95b |
| Fixed in 6.10.14 with commit bf0de0f9a0544c11f96f93206da04ab87dcea1f4 |
| Fixed in 6.11.3 with commit 65d11eb276836d49003a8060cf31fa2284ad1047 |
| Fixed in 6.12 with commit 41fd1e94066a815a7ab0a7025359e9b40e4b3576 |
| |
| 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-2024-49867 |
| 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/cd686dfff63f27d712877aef5b962fbf6b8bc264 |
| https://git.kernel.org/stable/c/a71349b692ab34ea197949e13e3cc42570fe73d9 |
| https://git.kernel.org/stable/c/70b60c8d9b42763d6629e44f448aa5d8ae477d61 |
| https://git.kernel.org/stable/c/4c98fe0dfa2ae83c4631699695506d8941db4bfe |
| https://git.kernel.org/stable/c/9da40aea63f8769f28afb91aea0fac4cf6fbbb65 |
| https://git.kernel.org/stable/c/ed87190e9d9c80aad220fb6b0b03a84d22e2c95b |
| https://git.kernel.org/stable/c/bf0de0f9a0544c11f96f93206da04ab87dcea1f4 |
| https://git.kernel.org/stable/c/65d11eb276836d49003a8060cf31fa2284ad1047 |
| https://git.kernel.org/stable/c/41fd1e94066a815a7ab0a7025359e9b40e4b3576 |
