Message-ID: <0000000000000ecbd306202ab365@google.com>
Date: Tue, 20 Aug 2024 22:20:25 -0700
From: syzbot <syzbot+1116a7b7b96b9c426a1a@...kaller.appspotmail.com>
To: chandan.babu@...cle.com, djwong@...nel.org, linux-kernel@...r.kernel.org, 
	linux-xfs@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [xfs?] possible deadlock in xfs_fs_dirty_inode (2)

Hello,

syzbot found the following issue on:

HEAD commit:    47ac09b91bef Linux 6.11-rc4
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11770de5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df2f0ed7e30a639d
dashboard link: https://syzkaller.appspot.com/bug?extid=1116a7b7b96b9c426a1a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-47ac09b9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6db2a1c6b666/vmlinux-47ac09b9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b1c782255526/bzImage-47ac09b9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1116a7b7b96b9c426a1a@...kaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc4-syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/80 is trying to acquire lock:
ffff888038052610 (sb_internal#2){.+.+}-{0:0}, at: xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691

but task is already holding lock:
ffffffff8ea2fd20 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6841 [inline]
ffffffff8ea2fd20 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbb4/0x35a0 mm/vmscan.c:7223

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       __fs_reclaim_acquire mm/page_alloc.c:3818 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3832
       might_alloc include/linux/sched/mm.h:334 [inline]
       slab_pre_alloc_hook mm/slub.c:3939 [inline]
       slab_alloc_node mm/slub.c:4017 [inline]
       __do_kmalloc_node mm/slub.c:4157 [inline]
       __kmalloc_noprof+0xa9/0x400 mm/slub.c:4170
       kmalloc_noprof include/linux/slab.h:685 [inline]
       xfs_attr_shortform_list+0x753/0x1900 fs/xfs/xfs_attr_list.c:117
       xfs_attr_list+0x1d0/0x270 fs/xfs/xfs_attr_list.c:595
       xfs_vn_listxattr+0x1d2/0x2c0 fs/xfs/xfs_xattr.c:341
       vfs_listxattr fs/xattr.c:493 [inline]
       listxattr+0x107/0x290 fs/xattr.c:841
       path_listxattr fs/xattr.c:865 [inline]
       __do_sys_listxattr fs/xattr.c:877 [inline]
       __se_sys_listxattr fs/xattr.c:874 [inline]
       __x64_sys_listxattr+0x173/0x230 fs/xattr.c:874
       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

-> #1 (&xfs_nondir_ilock_class#3){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1695
       xfs_fs_dirty_inode+0x18d/0x250 fs/xfs/xfs_super.c:693
       __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2486
       generic_update_time+0xb0/0xc0 fs/inode.c:2004
       xfs_vn_update_time+0x2a5/0x600 fs/xfs/xfs_iops.c:1085
       inode_update_time fs/inode.c:2016 [inline]
       __file_update_time fs/inode.c:2206 [inline]
       file_modified_flags+0x38a/0x4e0 fs/inode.c:2277
       xfs_file_write_checks+0x7f2/0x9b0 fs/xfs/xfs_file.c:461
       xfs_file_buffered_write+0x215/0xad0 fs/xfs/xfs_file.c:757
       __kernel_write_iter+0x40d/0x900 fs/read_write.c:523
       __kernel_write+0x120/0x180 fs/read_write.c:543
       __dump_emit+0x237/0x360 fs/coredump.c:816
       elf_core_dump+0x31d0/0x4720 fs/binfmt_elf.c:2068
       do_coredump+0x1b04/0x2a30 fs/coredump.c:767
       get_signal+0x13fa/0x1740 kernel/signal.c:2902
       arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
       exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
       irqentry_exit_to_user_mode+0x79/0x280 kernel/entry/common.c:231
       exc_page_fault+0x590/0x8c0 arch/x86/mm/fault.c:1542
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #0 (sb_internal#2){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
       __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1675 [inline]
       sb_start_intwrite include/linux/fs.h:1858 [inline]
       xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
       xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691
       __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2486
       mark_inode_dirty_sync include/linux/fs.h:2436 [inline]
       iput+0x1fe/0x930 fs/inode.c:1861
       __dentry_kill+0x20d/0x630 fs/dcache.c:610
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1055
       shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1082
       prune_dcache_sb+0x10f/0x180 fs/dcache.c:1163
       super_cache_scan+0x34f/0x4b0 fs/super.c:221
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
       shrink_one+0x43b/0x850 mm/vmscan.c:4815
       shrink_many mm/vmscan.c:4876 [inline]
       lru_gen_shrink_node mm/vmscan.c:4954 [inline]
       shrink_node+0x3799/0x3de0 mm/vmscan.c:5934
       kswapd_shrink_node mm/vmscan.c:6762 [inline]
       balance_pgdat mm/vmscan.c:6954 [inline]
       kswapd+0x1bcd/0x35a0 mm/vmscan.c:7223
       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

other info that might help us debug this:

Chain exists of:
  sb_internal#2 --> &xfs_nondir_ilock_class#3 --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&xfs_nondir_ilock_class#3);
                               lock(fs_reclaim);
  rlock(sb_internal#2);

 *** DEADLOCK ***

2 locks held by kswapd0/80:
 #0: ffffffff8ea2fd20 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6841 [inline]
 #0: ffffffff8ea2fd20 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbb4/0x35a0 mm/vmscan.c:7223
 #1: ffff8880380520e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff8880380520e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 UID: 0 PID: 80 Comm: kswapd0 Not tainted 6.11.0-rc4-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1675 [inline]
 sb_start_intwrite include/linux/fs.h:1858 [inline]
 xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
 xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691
 __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2486
 mark_inode_dirty_sync include/linux/fs.h:2436 [inline]
 iput+0x1fe/0x930 fs/inode.c:1861
 __dentry_kill+0x20d/0x630 fs/dcache.c:610
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1055
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1082
 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1163
 super_cache_scan+0x34f/0x4b0 fs/super.c:221
 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
 shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
 shrink_one+0x43b/0x850 mm/vmscan.c:4815
 shrink_many mm/vmscan.c:4876 [inline]
 lru_gen_shrink_node mm/vmscan.c:4954 [inline]
 shrink_node+0x3799/0x3de0 mm/vmscan.c:5934
 kswapd_shrink_node mm/vmscan.c:6762 [inline]
 balance_pgdat mm/vmscan.c:6954 [inline]
 kswapd+0x1bcd/0x35a0 mm/vmscan.c:7223
 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>


---
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