Date: Tue, 09 Sep 2025 16:28:30 -0700 [thread overview] > syzbot has found a reproducer for the following issue on: > > HEAD commit: 9dd1835ecda5 Merge tag 'dma-mapping-6.17-2025-09-09' of gi.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17f94b12580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=429771c55b615e85 > dashboard link: https://syzkaller.appspot.com/bug?extid=eb5b4ef634a018917f3c > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=160e4d62580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=160f6d62580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/63dc392685dc/disk-9dd1835e.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/3dfcfb97806e/vmlinux-9dd1835e.xz > kernel image: https://storage.googleapis.com/syzbot-assets/ddb10128aeb8/bzImage-9dd1835e.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/0b26d5f09478/mount_0.gz > fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=14aab562580000) > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+eb5b4ef634a018917f3c@xxxxxxxxxxxxxxxxxxxxxxxxx > > loop0: detected capacity change from 0 to 512 > ====================================================== > WARNING: possible circular locking dependency detected > syzkaller #0 Not tainted > ------------------------------------------------------ > syz.0.17/6097 is trying to acquire lock: > ffff88803dfbec58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] > ffff88803dfbec58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1786 [inline] > ffff88803dfbec58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024 > > but task is already holding lock: > ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:164 [inline] > ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:6425 [inline] > ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: __ext4_mark_inode_dirty+0x3eb/0x700 fs/ext4/inode.c:6506 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #2 (&ei->xattr_sem){++++}-{4:4}: > lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 > down_write+0x3a/0x50 kernel/locking/rwsem.c:1590 > ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] > ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2362 > ext4_initxattrs+0x9f/0x110 fs/ext4/xattr_security.c:44 > security_inode_init_security+0x29d/0x3f0 security/security.c:1852 > __ext4_new_inode+0x3314/0x3cb0 fs/ext4/ialloc.c:1325 If new inode can not be orphan, this report is false positive. > ext4_create+0x22d/0x460 fs/ext4/namei.c:2822 > lookup_open fs/namei.c:3708 [inline] > open_last_lookups fs/namei.c:3807 [inline] > path_openat+0x14fd/0x3840 fs/namei.c:4043 > do_filp_open+0x1fa/0x410 fs/namei.c:4073 > do_sys_openat2+0x121/0x1c0 fs/open.c:1435 > do_sys_open fs/open.c:1450 [inline] > __do_sys_openat fs/open.c:1466 [inline] > __se_sys_openat fs/open.c:1461 [inline] > __x64_sys_openat+0x138/0x170 fs/open.c:1461 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > -> #1 (jbd2_handle){++++}-{0:0}: > lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 > start_this_handle+0x1fa7/0x21c0 fs/jbd2/transaction.c:444 > jbd2__journal_start+0x2c1/0x5b0 fs/jbd2/transaction.c:501 > __ext4_journal_start_sb+0x227/0x5c0 fs/ext4/ext4_jbd2.c:115 > __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] > ext4_do_writepages+0xf6f/0x4600 fs/ext4/inode.c:2913 > ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025 > do_writepages+0x32b/0x550 mm/page-writeback.c:2634 > __writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1680 > writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976 > __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 > wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 > wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] > wb_do_writeback fs/fs-writeback.c:2315 [inline] > wb_workfn+0xaf4/0xf00 fs/fs-writeback.c:2343 > process_one_work kernel/workqueue.c:3236 [inline] > process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 > worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 > kthread+0x70e/0x8a0 kernel/kthread.c:463 > ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > -> #0 (&sbi->s_writepages_rwsem){++++}-{0:0}: > check_prev_add kernel/locking/lockdep.c:3165 [inline] > check_prevs_add kernel/locking/lockdep.c:3284 [inline] > validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 > __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 > lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 > percpu_down_read_internal+0x48/0x1d0 include/linux/percpu-rwsem.h:53 > percpu_down_read include/linux/percpu-rwsem.h:77 [inline] > ext4_writepages_down_read fs/ext4/ext4.h:1786 [inline] > ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024 > do_writepages+0x32b/0x550 mm/page-writeback.c:2634 > __writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1680 > writeback_single_inode+0x1d5/0x640 fs/fs-writeback.c:1801 > write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2864 > iput_final fs/inode.c:1884 [inline] > iput+0x5b9/0x9d0 fs/inode.c:1923 > ext4_xattr_block_set+0x1fce/0x2ac0 fs/ext4/xattr.c:2194 > ext4_xattr_move_to_block fs/ext4/xattr.c:2659 [inline] > ext4_xattr_make_inode_space fs/ext4/xattr.c:2734 [inline] > ext4_expand_extra_isize_ea+0x12d5/0x1ea0 fs/ext4/xattr.c:2822 > __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6385 > ext4_try_to_expand_extra_isize fs/ext4/inode.c:6428 [inline] > __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6506 > ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254 > evict+0x504/0x9c0 fs/inode.c:810 > ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:474 > __ext4_fill_super fs/ext4/super.c:5609 [inline] > ext4_fill_super+0x57fa/0x60b0 fs/ext4/super.c:5728 > get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 > vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 > do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 > do_mount fs/namespace.c:4136 [inline] > __do_sys_mount fs/namespace.c:4347 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4324 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > other info that might help us debug this: > > Chain exists of: > &sbi->s_writepages_rwsem --> jbd2_handle --> &ei->xattr_sem > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&ei->xattr_sem); > lock(jbd2_handle); > lock(&ei->xattr_sem); > rlock(&sbi->s_writepages_rwsem); > > *** DEADLOCK *** > > 3 locks held by syz.0.17/6097: > #0: ffff88803dfbc0d0 (&type->s_umount_key#26/1){+.+.}-{4:4}, at: alloc_super+0x204/0x990 fs/super.c:345 > #1: ffff88803dfbc778 (sb_internal){.+.+}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] > #1: ffff88803dfbc778 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1799 [inline] > #1: ffff88803dfbc778 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1982 [inline] > #1: ffff88803dfbc778 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x2d6/0xee0 fs/ext4/inode.c:215 > #2: ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:164 [inline] > #2: ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:6425 [inline] > #2: ffff88823bf82560 (&ei->xattr_sem){++++}-{4:4}, at: __ext4_mark_inode_dirty+0x3eb/0x700 fs/ext4/inode.c:6506 > > stack backtrace: > CPU: 1 UID: 0 PID: 6097 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 > Call Trace: > <TASK> > dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 > print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 > check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 > check_prev_add kernel/locking/lockdep.c:3165 [inline] > check_prevs_add kernel/locking/lockdep.c:3284 [inline] > validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 > __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 > lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 > percpu_down_read_internal+0x48/0x1d0 include/linux/percpu-rwsem.h:53 > percpu_down_read include/linux/percpu-rwsem.h:77 [inline] > ext4_writepages_down_read fs/ext4/ext4.h:1786 [inline] > ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024 > do_writepages+0x32b/0x550 mm/page-writeback.c:2634 > __writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1680 > writeback_single_inode+0x1d5/0x640 fs/fs-writeback.c:1801 > write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2864 > iput_final fs/inode.c:1884 [inline] > iput+0x5b9/0x9d0 fs/inode.c:1923 > ext4_xattr_block_set+0x1fce/0x2ac0 fs/ext4/xattr.c:2194 > ext4_xattr_move_to_block fs/ext4/xattr.c:2659 [inline] > ext4_xattr_make_inode_space fs/ext4/xattr.c:2734 [inline] > ext4_expand_extra_isize_ea+0x12d5/0x1ea0 fs/ext4/xattr.c:2822 > __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6385 > ext4_try_to_expand_extra_isize fs/ext4/inode.c:6428 [inline] > __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6506 > ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254 > evict+0x504/0x9c0 fs/inode.c:810 > ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:474 > __ext4_fill_super fs/ext4/super.c:5609 [inline] > ext4_fill_super+0x57fa/0x60b0 fs/ext4/super.c:5728 > get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 > vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 > do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 > do_mount fs/namespace.c:4136 [inline] > __do_sys_mount fs/namespace.c:4347 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4324 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fefaad0038a > Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffdb287c378 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007ffdb287c400 RCX: 00007fefaad0038a > RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffdb287c3c0 > RBP: 0000200000000180 R08: 00007ffdb287c400 R09: 0000000000800700 > R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0 > R13: 00007ffdb287c3c0 R14: 0000000000000473 R15: 0000200000000680 > </TASK> > ------------[ cut here ]------------ > EA inode 11 i_nlink=2 > WARNING: CPU: 1 PID: 6097 at fs/ext4/xattr.c:1053 ext4_xattr_inode_update_ref+0x534/0x5d0 fs/ext4/xattr.c:1051 > Modules linked in: > CPU: 1 UID: 0 PID: 6097 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 > RIP: 0010:ext4_xattr_inode_update_ref+0x534/0x5d0 fs/ext4/xattr.c:1051 > Code: 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 0f 85 86 00 00 00 41 8b 14 24 48 c7 c7 60 6d 1f 8b 4c 89 fe e8 1d 9a 07 ff 90 <0f> 0b 90 90 48 bb 00 00 00 00 00 fc ff df e9 bb fd ff ff e8 a4 2b > RSP: 0018:ffffc900041bf1a0 EFLAGS: 00010246 > RAX: 3b7a600244a15000 RBX: dffffc0000000000 RCX: ffff88803cfa3b80 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc900041bf298 R08: 0000000000000000 R09: 0000000000000000 > R10: dffffc0000000000 R11: ffffed1017124863 R12: ffff888049711b30 > R13: 1ffff110092e2366 R14: 00000000ffffffff R15: 000000000000000b > FS: 000055556e3f9500(0000) GS:ffff8881269bf000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f24cdec2e9c CR3: 000000002c16a000 CR4: 00000000003526f0 > Call Trace: > <TASK> > ext4_xattr_inode_dec_ref fs/ext4/xattr.c:1076 [inline] > ext4_xattr_set_entry+0xabb/0x1e20 fs/ext4/xattr.c:1714 > ext4_xattr_ibody_set+0x254/0x6a0 fs/ext4/xattr.c:2263 > ext4_xattr_move_to_block fs/ext4/xattr.c:2666 [inline] > ext4_xattr_make_inode_space fs/ext4/xattr.c:2734 [inline] > ext4_expand_extra_isize_ea+0x13a8/0x1ea0 fs/ext4/xattr.c:2822 > __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6385 > ext4_try_to_expand_extra_isize fs/ext4/inode.c:6428 [inline] > __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6506 > ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254 > evict+0x504/0x9c0 fs/inode.c:810 > ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:474 > __ext4_fill_super fs/ext4/super.c:5609 [inline] > ext4_fill_super+0x57fa/0x60b0 fs/ext4/super.c:5728 > get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 > vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 > do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 > do_mount fs/namespace.c:4136 [inline] > __do_sys_mount fs/namespace.c:4347 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4324 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fefaad0038a > Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffdb287c378 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 00007ffdb287c400 RCX: 00007fefaad0038a > RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffdb287c3c0 > RBP: 0000200000000180 R08: 00007ffdb287c400 R09: 0000000000800700 > R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0 > R13: 00007ffdb287c3c0 R14: 0000000000000473 R15: 0000200000000680 > </TASK>
