====================================================== WARNING: possible circular locking dependency detected 6.1.135-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.2135/13810 is trying to acquire lock: ffff888077348ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xca/0x730 fs/gfs2/quota.c:682 but task is already holding lock: ffff88804cdb85e8 (&ip->i_rw_mutex){++++}-{3:3}, at: gfs2_unstuff_dinode+0x9b/0x1770 fs/gfs2/bmap.c:163 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+0x42/0x2d0 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x155/0x13e0 fs/gfs2/bmap.c:856 gfs2_iomap_get+0xc1/0x120 fs/gfs2/bmap.c:1396 bh_get+0x241/0x730 fs/gfs2/quota.c:385 qdsb_get+0x21c/0x3c0 fs/gfs2/quota.c:522 gfs2_quota_hold+0x194/0x5d0 fs/gfs2/quota.c:608 gfs2_quota_lock+0xa0/0x7d0 fs/gfs2/quota.c:1076 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline] alloc_dinode+0x164/0x4f0 fs/gfs2/inode.c:393 gfs2_create_inode+0xc79/0x1410 fs/gfs2/inode.c:711 gfs2_atomic_open+0xce/0x210 fs/gfs2/inode.c:1292 atomic_open fs/namei.c:3345 [inline] lookup_open fs/namei.c:3453 [inline] open_last_lookups fs/namei.c:3550 [inline] path_openat+0xe20/0x2e70 fs/namei.c:3780 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810 file_open_name fs/open.c:1263 [inline] filp_open+0x173/0x1d0 fs/open.c:1283 do_coredump+0x1b7c/0x21f0 fs/coredump.c:696 get_signal+0x10aa/0x1350 kernel/signal.c:2857 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 -> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 do_qc+0xca/0x730 fs/gfs2/quota.c:682 gfs2_quota_change+0x2f5/0x8e0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18b3/0x2070 fs/gfs2/rgrp.c:2494 __gfs2_unstuff_inode fs/gfs2/bmap.c:109 [inline] gfs2_unstuff_dinode+0x1f5/0x1770 fs/gfs2/bmap.c:168 gfs2_iomap_begin_write fs/gfs2/bmap.c:1036 [inline] gfs2_iomap_begin+0x989/0x1340 fs/gfs2/bmap.c:1112 iomap_iter+0x6c6/0x1040 fs/iomap/iter.c:91 iomap_file_buffered_write+0x1b4/0x880 fs/iomap/buffered-io.c:846 gfs2_file_buffered_write+0x4fe/0x880 fs/gfs2/file.c:1057 gfs2_file_write_iter+0x42c/0xdf0 fs/gfs2/file.c:1158 __kernel_write_iter+0x26d/0x630 fs/read_write.c:517 __kernel_write+0xec/0x140 fs/read_write.c:537 __dump_emit+0x202/0x310 fs/coredump.c:804 elf_core_dump+0x2996/0x3490 fs/binfmt_elf.c:2292 do_coredump+0x1573/0x21f0 fs/coredump.c:755 get_signal+0x10aa/0x1350 kernel/signal.c:2857 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490 asm_exc_page_fault+0x22/0x30 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.3.2135/13810: #0: ffff88807c456460 (sb_writers#33){.+.+}-{0:0}, at: do_coredump+0x1552/0x21f0 fs/coredump.c:754 #1: ffff88804cdb8150 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff88804cdb8150 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: gfs2_file_write_iter+0x308/0xdf0 fs/gfs2/file.c:1115 #2: ffff88807c456650 (sb_internal#7){.+.+}-{0:0}, at: gfs2_trans_begin+0x6b/0xe0 fs/gfs2/trans.c:118 #3: ffff888077349058 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x50d/0x880 fs/gfs2/trans.c:87 #4: ffff88804cdb85e8 (&ip->i_rw_mutex){++++}-{3:3}, at: gfs2_unstuff_dinode+0x9b/0x1770 fs/gfs2/bmap.c:163 stack backtrace: CPU: 1 PID: 13810 Comm: syz.3.2135 Not tainted 6.1.135-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 do_qc+0xca/0x730 fs/gfs2/quota.c:682 gfs2_quota_change+0x2f5/0x8e0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18b3/0x2070 fs/gfs2/rgrp.c:2494 __gfs2_unstuff_inode fs/gfs2/bmap.c:109 [inline] gfs2_unstuff_dinode+0x1f5/0x1770 fs/gfs2/bmap.c:168 gfs2_iomap_begin_write fs/gfs2/bmap.c:1036 [inline] gfs2_iomap_begin+0x989/0x1340 fs/gfs2/bmap.c:1112 iomap_iter+0x6c6/0x1040 fs/iomap/iter.c:91 iomap_file_buffered_write+0x1b4/0x880 fs/iomap/buffered-io.c:846 gfs2_file_buffered_write+0x4fe/0x880 fs/gfs2/file.c:1057 gfs2_file_write_iter+0x42c/0xdf0 fs/gfs2/file.c:1158 __kernel_write_iter+0x26d/0x630 fs/read_write.c:517 __kernel_write+0xec/0x140 fs/read_write.c:537 __dump_emit+0x202/0x310 fs/coredump.c:804 elf_core_dump+0x2996/0x3490 fs/binfmt_elf.c:2292 do_coredump+0x1573/0x21f0 fs/coredump.c:755 get_signal+0x10aa/0x1350 kernel/signal.c:2857 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x864b8ed7 Code: Unable to access opcode bytes at 0x864b8ead. RSP: 002b:0000200000000298 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f3a4c5b5fa0 RCX: 00007f3a4c38e969 RDX: 0000200000000000 RSI: 0000200000000290 RDI: 0000000020000000 RBP: 00007f3a4c410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000180 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3a4c5b5fa0 R15: 00007ffd7a0e8f48