====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.63/4742 is trying to acquire lock: ffff88801a74cae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 but task is already holding lock: ffff888072f9ae38 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x28e/0x1a90 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+0x42/0x2d0 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x164/0x1390 fs/gfs2/bmap.c:862 gfs2_iomap_get+0xeb/0x170 fs/gfs2/bmap.c:1413 bh_get+0x26d/0x780 fs/gfs2/quota.c:385 qdsb_get+0x21c/0x3c0 fs/gfs2/quota.c:522 gfs2_quota_hold+0x18d/0x5b0 fs/gfs2/quota.c:608 gfs2_quota_lock+0xa0/0x7f0 fs/gfs2/quota.c:1076 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline] gfs2_page_mkwrite+0xc7d/0x13e0 fs/gfs2/file.c:483 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 wp_page_shared+0x167/0x370 mm/memory.c:3358 handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x1b1b/0x3d40 mm/memory.c:5292 fixup_user_fault+0x282/0x4a0 mm/gup.c:1382 fault_in_safe_writeable+0x11b/0x210 mm/gup.c:1878 fault_in_iov_iter_writeable+0xbf/0x2f0 lib/iov_iter.c:399 gfs2_file_read_iter+0x965/0xc50 fs/gfs2/file.c:993 call_read_iter include/linux/fs.h:2265 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x471/0x960 fs/read_write.c:470 ksys_read+0x14d/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 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+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747 do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 gfs2_quota_change+0x293/0x7a0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18e1/0x20a0 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x4eb/0x1a90 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x15d/0x200 fs/gfs2/bmap.c:1426 gfs2_allocate_page_backing+0x134/0x220 fs/gfs2/file.c:395 gfs2_page_mkwrite+0x10c7/0x13e0 fs/gfs2/file.c:525 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 wp_page_shared+0x167/0x370 mm/memory.c:3358 handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x1b1b/0x3d40 mm/memory.c:5292 fixup_user_fault+0x282/0x4a0 mm/gup.c:1382 fault_in_safe_writeable+0x11b/0x210 mm/gup.c:1878 fault_in_iov_iter_writeable+0xbf/0x2f0 lib/iov_iter.c:399 gfs2_file_read_iter+0x965/0xc50 fs/gfs2/file.c:993 call_read_iter include/linux/fs.h:2265 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x471/0x960 fs/read_write.c:470 ksys_read+0x14d/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 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.2.63/4742: #0: ffff88803070d4e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff88807d60f1d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #1: ffff88807d60f1d8 (&mm->mmap_lock){++++}-{3:3}, at: fault_in_safe_writeable+0xf4/0x210 mm/gup.c:1876 #2: ffff888028b04558 (sb_pagefaults#3){.+.+}-{0:0}, at: do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 #3: ffff888028b04650 (sb_internal#6){.+.+}-{0:0}, at: gfs2_trans_begin+0x6b/0xe0 fs/gfs2/trans.c:118 #4: ffff88801a74d058 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x533/0x8b0 fs/gfs2/trans.c:87 #5: ffff888072f9ae38 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x28e/0x1a90 fs/gfs2/bmap.c:685 stack backtrace: CPU: 0 PID: 4742 Comm: syz.2.63 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x2f8/0x400 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+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747 do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 gfs2_quota_change+0x293/0x7a0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18e1/0x20a0 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x4eb/0x1a90 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x15d/0x200 fs/gfs2/bmap.c:1426 gfs2_allocate_page_backing+0x134/0x220 fs/gfs2/file.c:395 gfs2_page_mkwrite+0x10c7/0x13e0 fs/gfs2/file.c:525 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 wp_page_shared+0x167/0x370 mm/memory.c:3358 handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x1b1b/0x3d40 mm/memory.c:5292 fixup_user_fault+0x282/0x4a0 mm/gup.c:1382 fault_in_safe_writeable+0x11b/0x210 mm/gup.c:1878 fault_in_iov_iter_writeable+0xbf/0x2f0 lib/iov_iter.c:399 gfs2_file_read_iter+0x965/0xc50 fs/gfs2/file.c:993 call_read_iter include/linux/fs.h:2265 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x471/0x960 fs/read_write.c:470 ksys_read+0x14d/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f26b4d9fb19 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:00007f26b2fd5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f26b5026180 RCX: 00007f26b4d9fb19 RDX: 00000000fffffeb1 RSI: 0000200000038940 RDI: 0000000000000007 RBP: 00007f26b4e37b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f26b5026218 R14: 00007f26b5026180 R15: 00007fff574cfe48