gfs2: fsid=syz:syz.0: first mount done, others may mount ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.270/6984 is trying to acquire lock: ffff88801d734ae8 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xa1/0x5f0 fs/gfs2/quota.c:689 but task is already holding lock: ffff88806e7485e8 (&ip->i_rw_mutex){++++}-{3:3} , at: __gfs2_iomap_alloc+0x289/0x1ab0 fs/gfs2/bmap.c:685 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ip->i_rw_mutex){++++}-{3:3} : down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x168/0x1390 fs/gfs2/bmap.c:862 gfs2_iomap_get+0xef/0x170 fs/gfs2/bmap.c:1440 bh_get+0x251/0x760 fs/gfs2/quota.c:401 qdsb_get+0x210/0x330 fs/gfs2/quota.c:535 gfs2_quota_hold+0x191/0x5c0 fs/gfs2/quota.c:615 gfs2_quota_lock+0xba/0x7b0 fs/gfs2/quota.c:1070 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline] gfs2_page_mkwrite+0xc96/0x13f0 fs/gfs2/file.c:484 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 do_shared_fault mm/memory.c:4717 [inline] do_fault mm/memory.c:4779 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353 fixup_user_fault+0x386/0x750 mm/gup.c:1330 fault_in_safe_writeable+0x11f/0x220 mm/gup.c:1868 fault_in_iov_iter_writeable+0xc3/0x300 lib/iov_iter.c:259 gfs2_file_read_iter+0x969/0xc60 fs/gfs2/file.c:997 call_read_iter include/linux/fs.h:2012 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x486/0x990 fs/read_write.c:470 ksys_read+0x151/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 do_qc+0xa1/0x5f0 fs/gfs2/quota.c:689 gfs2_quota_change+0x28f/0x7a0 fs/gfs2/quota.c:1289 gfs2_alloc_blocks+0x1896/0x2050 fs/gfs2/rgrp.c:2496 __gfs2_iomap_alloc+0x4da/0x1ab0 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x161/0x200 fs/gfs2/bmap.c:1453 gfs2_allocate_page_backing+0x138/0x220 fs/gfs2/file.c:396 gfs2_page_mkwrite+0x1106/0x13f0 fs/gfs2/file.c:526 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 do_shared_fault mm/memory.c:4717 [inline] do_fault mm/memory.c:4779 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353 fixup_user_fault+0x386/0x750 mm/gup.c:1330 fault_in_safe_writeable+0x11f/0x220 mm/gup.c:1868 fault_in_iov_iter_writeable+0xc3/0x300 lib/iov_iter.c:259 gfs2_file_read_iter+0x969/0xc60 fs/gfs2/file.c:997 call_read_iter include/linux/fs.h:2012 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x486/0x990 fs/read_write.c:470 ksys_read+0x151/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ip->i_rw_mutex); lock(&sdp->sd_quota_mutex); lock(&ip->i_rw_mutex); lock(&sdp->sd_quota_mutex); *** DEADLOCK *** 6 locks held by syz.8.270/6984: #0: ffff88807a5e7748 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff88802eade0a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:146 [inline] #1: ffff88802eade0a0 (&mm->mmap_lock){++++}-{3:3}, at: fixup_user_fault+0x3ec/0x750 mm/gup.c:1352 #2: ffff888026de6510 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 #3: ffff888026de6608 (sb_internal#4){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #4: ffff88801d735060 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x537/0x8b0 fs/gfs2/trans.c:87 #5: ffff88806e7485e8 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x289/0x1ab0 fs/gfs2/bmap.c:685 stack backtrace: CPU: 1 PID: 6984 Comm: syz.8.270 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 do_qc+0xa1/0x5f0 fs/gfs2/quota.c:689 gfs2_quota_change+0x28f/0x7a0 fs/gfs2/quota.c:1289 gfs2_alloc_blocks+0x1896/0x2050 fs/gfs2/rgrp.c:2496 __gfs2_iomap_alloc+0x4da/0x1ab0 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x161/0x200 fs/gfs2/bmap.c:1453 gfs2_allocate_page_backing+0x138/0x220 fs/gfs2/file.c:396 gfs2_page_mkwrite+0x1106/0x13f0 fs/gfs2/file.c:526 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 do_shared_fault mm/memory.c:4717 [inline] do_fault mm/memory.c:4779 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353 fixup_user_fault+0x386/0x750 mm/gup.c:1330 fault_in_safe_writeable+0x11f/0x220 mm/gup.c:1868 fault_in_iov_iter_writeable+0xc3/0x300 lib/iov_iter.c:259 gfs2_file_read_iter+0x969/0xc60 fs/gfs2/file.c:997 call_read_iter include/linux/fs.h:2012 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x486/0x990 fs/read_write.c:470 ksys_read+0x151/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f697a39e1d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f69785f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f697a625fa0 RCX: 00007f697a39e1d9 RDX: 000000000000effd RSI: 0000200000005f80 RDI: 0000000000000004 RBP: 00007f697a435888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f697a626038 R14: 00007f697a625fa0 R15: 00007ffe517023e8 kcov: kcov_task_exit: t = ffff888021d08000, kcov->t = ffff888021d08000