====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.307/7704 is trying to acquire lock: ffff888077884ae8 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xaf/0x670 fs/gfs2/quota.c:689 but task is already holding lock: ffff888066c405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1526 [inline] ffff888066c405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x1c7d/0x2d70 fs/gfs2/bmap.c:1850 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+0x159/0x13f0 fs/gfs2/bmap.c:856 gfs2_iomap_get+0xc5/0x120 fs/gfs2/bmap.c:1410 bh_get+0x225/0x710 fs/gfs2/quota.c:401 qdsb_get+0x210/0x330 fs/gfs2/quota.c:535 gfs2_quota_hold+0x198/0x5e0 fs/gfs2/quota.c:615 punch_hole+0x974/0x2d70 fs/gfs2/bmap.c:1811 gfs2_iomap_end+0x4f6/0x6b0 fs/gfs2/bmap.c:1171 iomap_iter+0x21e/0xec0 fs/iomap/iter.c:79 iomap_file_buffered_write+0xb8b/0xd10 fs/iomap/buffered-io.c:974 gfs2_file_buffered_write+0x4bd/0x820 fs/gfs2/file.c:1060 gfs2_file_write_iter+0x427/0xe10 fs/gfs2/file.c:1158 __kernel_write_iter+0x274/0x670 fs/read_write.c:517 dump_emit_page fs/coredump.c:957 [inline] dump_user_range+0x3f6/0x800 fs/coredump.c:984 elf_core_dump+0x3114/0x36e0 fs/binfmt_elf.c:2184 do_coredump+0x1755/0x2480 fs/coredump.c:833 get_signal+0x1133/0x1400 kernel/signal.c:2888 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315 exc_page_fault+0x8f/0x110 arch/x86/mm/fault.c:1524 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 -> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 do_qc+0xaf/0x670 fs/gfs2/quota.c:689 gfs2_quota_change+0x2b9/0x800 fs/gfs2/quota.c:1289 punch_hole+0x280c/0x2d70 fs/gfs2/bmap.c:1951 gfs2_iomap_end+0x4f6/0x6b0 fs/gfs2/bmap.c:1171 iomap_iter+0x21e/0xec0 fs/iomap/iter.c:79 iomap_file_buffered_write+0xb8b/0xd10 fs/iomap/buffered-io.c:974 gfs2_file_buffered_write+0x4bd/0x820 fs/gfs2/file.c:1060 gfs2_file_write_iter+0x427/0xe10 fs/gfs2/file.c:1158 __kernel_write_iter+0x274/0x670 fs/read_write.c:517 dump_emit_page fs/coredump.c:957 [inline] dump_user_range+0x3f6/0x800 fs/coredump.c:984 elf_core_dump+0x3114/0x36e0 fs/binfmt_elf.c:2184 do_coredump+0x1755/0x2480 fs/coredump.c:833 get_signal+0x1133/0x1400 kernel/signal.c:2888 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315 exc_page_fault+0x8f/0x110 arch/x86/mm/fault.c:1524 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 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 *** 5 locks held by syz.0.307/7704: #0: ffff888063812418 (sb_writers#30){.+.+}-{0:0}, at: do_coredump+0x1734/0x2480 fs/coredump.c:832 #1: ffff888066c40160 (&sb->s_type->i_mutex_key#34){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff888066c40160 (&sb->s_type->i_mutex_key#34){+.+.}-{3:3}, at: gfs2_file_write_iter+0x304/0xe10 fs/gfs2/file.c:1115 #2: ffff888063812608 (sb_internal#6){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #3: ffff888077885060 (&sdp->sd_log_flush_lock){++++}-{3:3}, at: __gfs2_trans_begin+0x511/0x880 fs/gfs2/trans.c:87 #4: ffff888066c405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1526 [inline] #4: ffff888066c405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x1c7d/0x2d70 fs/gfs2/bmap.c:1850 stack backtrace: CPU: 1 PID: 7704 Comm: syz.0.307 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 do_qc+0xaf/0x670 fs/gfs2/quota.c:689 gfs2_quota_change+0x2b9/0x800 fs/gfs2/quota.c:1289 punch_hole+0x280c/0x2d70 fs/gfs2/bmap.c:1951 gfs2_iomap_end+0x4f6/0x6b0 fs/gfs2/bmap.c:1171 iomap_iter+0x21e/0xec0 fs/iomap/iter.c:79 iomap_file_buffered_write+0xb8b/0xd10 fs/iomap/buffered-io.c:974 gfs2_file_buffered_write+0x4bd/0x820 fs/gfs2/file.c:1060 gfs2_file_write_iter+0x427/0xe10 fs/gfs2/file.c:1158 __kernel_write_iter+0x274/0x670 fs/read_write.c:517 dump_emit_page fs/coredump.c:957 [inline] dump_user_range+0x3f6/0x800 fs/coredump.c:984 elf_core_dump+0x3114/0x36e0 fs/binfmt_elf.c:2184 do_coredump+0x1755/0x2480 fs/coredump.c:833 get_signal+0x1133/0x1400 kernel/signal.c:2888 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315 exc_page_fault+0x8f/0x110 arch/x86/mm/fault.c:1524 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7ff82bf8f751 Code: 00 00 00 00 00 0f 1f 40 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 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007ff82c1e6090 RCX: 00007ff82bf8f749 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007ff82c013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ff82c1e6128 R14: 00007ff82c1e6090 R15: 00007ffd3c5325a8