kernel.git/fs/btrfs, branch linux-4.19.y

btrfs: reinitialize delayed ref list after deleting it from the list

2024-11-17T13:58:07Z

commit c9a75ec45f1111ef530ab186c2a7684d0a0c9245 upstream. At insert_delayed_ref() if we need to update the action of an existing ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's ref_add_list using list_del(), which leaves the ref's add_list member not reinitialized, as list_del() sets the next and prev members of the list to LIST_POISON1 and LIST_POISON2, respectively. If later we end up calling drop_delayed_ref() against the ref, which can happen during merging or when destroying delayed refs due to a transaction abort, we can trigger a crash since at drop_delayed_ref() we call list_empty() against the ref's add_list, which returns false since the list was not reinitialized after the list_del() and as a consequence we call list_del() again at drop_delayed_ref(). This results in an invalid list access since the next and prev members are set to poison pointers, resulting in a splat if CONFIG_LIST_HARDENED and CONFIG_DEBUG_LIST are set or invalid poison pointer dereferences otherwise. So fix this by deleting from the list with list_del_init() instead. Fixes: 1d57ee941692 ("btrfs: improve delayed refs iterations") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Johannes Thumshirn Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: wait for fixup workers before stopping cleaner kthread during umount

2024-11-08T15:19:15Z

commit 41fd1e94066a815a7ab0a7025359e9b40e4b3576 upstream. 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: __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 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 ================================================================== Reported-by: syzbot+8aaf2df2ef0164ffe1fb@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/66fb36b1.050a0220.aab67.003b.GAE@google.com/ CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Qu Wenruo Reviewed-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: initialize location to fix -Wmaybe-uninitialized in btrfs_lookup_dentry()

2024-09-12T09:02:54Z

[ Upstream commit b8e947e9f64cac9df85a07672b658df5b2bcff07 ] Some arch + compiler combinations report a potentially unused variable location in btrfs_lookup_dentry(). This is a false alert as the variable is passed by value and always valid or there's an error. The compilers cannot probably reason about that although btrfs_inode_by_name() is in the same file. > + /kisskb/src/fs/btrfs/inode.c: error: 'location.objectid' may be used +uninitialized in this function [-Werror=maybe-uninitialized]: => 5603:9 > + /kisskb/src/fs/btrfs/inode.c: error: 'location.type' may be used +uninitialized in this function [-Werror=maybe-uninitialized]: => 5674:5 m68k-gcc8/m68k-allmodconfig mips-gcc8/mips-allmodconfig powerpc-gcc5/powerpc-all{mod,yes}config powerpc-gcc5/ppc64_defconfig Initialize it to zero, this should fix the warnings and won't change the behaviour as btrfs_inode_by_name() accepts only a root or inode item types, otherwise returns an error. Reported-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/linux-btrfs/bd4e9928-17b3-9257-8ba7-6b7f9bbb639a@linux-m68k.org/ Reviewed-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: clean up our handling of refs == 0 in snapshot delete

2024-09-12T09:02:53Z

[ Upstream commit b8ccef048354074a548f108e51d0557d6adfd3a3 ] In reada we BUG_ON(refs == 0), which could be unkind since we aren't holding a lock on the extent leaf and thus could get a transient incorrect answer. In walk_down_proc we also BUG_ON(refs == 0), which could happen if we have extent tree corruption. Change that to return -EUCLEAN. In do_walk_down() we catch this case and handle it correctly, however we return -EIO, which -EUCLEAN is a more appropriate error code. Finally in walk_up_proc we have the same BUG_ON(refs == 0), so convert that to proper error handling. Also adjust the error message so we can actually do something with the information. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: replace BUG_ON with ASSERT in walk_down_proc()

2024-09-12T09:02:53Z

[ Upstream commit 1f9d44c0a12730a24f8bb75c5e1102207413cc9b ] We have a couple of areas where we check to make sure the tree block is locked before looking up or messing with references. This is old code so it has this as BUG_ON(). Convert this to ASSERT() for developers. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: delete pointless BUG_ON check on quota root in btrfs_qgroup_account_extent()

2024-09-04T11:13:03Z

[ Upstream commit f40a3ea94881f668084f68f6b9931486b1606db0 ] The BUG_ON is deep in the qgroup code where we can expect that it exists. A NULL pointer would cause a crash. It was added long ago in 550d7a2ed5db35 ("btrfs: qgroup: Add new qgroup calculation function btrfs_qgroup_account_extents()."). It maybe made sense back then as the quota enable/disable state machine was not that robust as it is nowadays, so we can just delete it. Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: send: handle unexpected data in header buffer in begin_cmd()

2024-09-04T11:13:03Z

[ Upstream commit e80e3f732cf53c64b0d811e1581470d67f6c3228 ] Change BUG_ON to a proper error handling in the unlikely case of seeing data when the command is started. This is supposed to be reset when the command is finished (send_cmd, send_encoded_extent). Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: handle invalid root reference found in may_destroy_subvol()

2024-09-04T11:13:03Z

[ Upstream commit 6fbc6f4ac1f4907da4fc674251527e7dc79ffbf6 ] The may_destroy_subvol() looks up a root by a key, allowing to do an inexact search when key->offset is -1. It's never expected to find such item, as it would break the allowed range of a root id. Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: change BUG_ON to assertion when checking for delayed_node root

2024-09-04T11:13:02Z

[ Upstream commit be73f4448b607e6b7ce41cd8ef2214fdf6e7986f ] The pointer to root is initialized in btrfs_init_delayed_node(), no need to check for it again. Change the BUG_ON to assertion. Reviewed-by: Josef Bacik Reviewed-by: Anand Jain Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: rename bitmap_set_bits() -> btrfs_bitmap_set_bits()

2024-09-04T11:13:00Z

commit 4ca532d64648d4776d15512caed3efea05ca7195 upstream. bitmap_set_bits() does not start with the FS' prefix and may collide with a new generic helper one day. It operates with the FS-specific types, so there's no change those two could do the same thing. Just add the prefix to exclude such possible conflict. Reviewed-by: Przemek Kitszel Acked-by: David Sterba Reviewed-by: Yury Norov Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman