Hello, I found a potential bug titled " possible deadlock in udf_page_mkwrite " with modified syzkaller in the Linux6.12.24(longterm maintenance, last updated on April 20, 2025). Unfortunately, I am unable to reproduce this bug. If you fix this issue, please add the following tag to the commit: Reported-by: Jianzhou Zhao luckd0g@163.com, xingwei lee xrivendell7@gmail.com,Penglei Jiang superman.xpt@gmail.com The commit of the kernel is : b6efa8ce222e58cfe2bbaa4e3329818c2b4bd74e kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=55f8591b98dd132 compiler: gcc version 11.4.0
------------[ cut here ]----------------------------------------- TITLE: possible deadlock in udf_page_mkwrite ------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 6.12.24 #3 Not tainted ------------------------------------------------------ syz.6.870/18445 is trying to acquire lock: ffff888053607700 (mapping.invalidate_lock#4){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:870 [inline] ffff888053607700 (mapping.invalidate_lock#4){++++}-{3:3}, at: udf_page_mkwrite+0x2af/0xa20 fs/udf/file.c:50
but task is already holding lock: ffff888044124518 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x17d/0x390 mm/memory.c:3161
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #9 (sb_pagefaults#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1716 [inline] sb_start_pagefault include/linux/fs.h:1881 [inline] udf_page_mkwrite+0x18b/0xa20 fs/udf/file.c:48 do_page_mkwrite+0x17d/0x390 mm/memory.c:3161 wp_page_shared mm/memory.c:3562 [inline] do_wp_page+0x1291/0x4860 mm/memory.c:3712 handle_pte_fault mm/memory.c:5786 [inline] __handle_mm_fault+0x150c/0x2a20 mm/memory.c:5913 handle_mm_fault+0x404/0xab0 mm/memory.c:6081 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
-> #8 (&vma->vm_lock->lock){++++}-{3:3}: down_write+0x92/0x200 kernel/locking/rwsem.c:1577 vma_start_write include/linux/mm.h:757 [inline] vma_link+0x268/0x490 mm/vma.c:1604 insert_vm_struct+0x197/0x3f0 mm/mmap.c:2011 __bprm_mm_init fs/exec.c:289 [inline] bprm_mm_init fs/exec.c:393 [inline] alloc_bprm+0x6d1/0xd30 fs/exec.c:1578 kernel_execve+0xb0/0x3d0 fs/exec.c:2010 try_to_run_init_process init/main.c:1397 [inline] kernel_init+0x154/0x2d0 init/main.c:1525 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #7 (&mm->mmap_lock){++++}-{3:3}: __might_fault mm/memory.c:6719 [inline] __might_fault+0x118/0x190 mm/memory.c:6713 _inline_copy_from_user include/linux/uaccess.h:162 [inline] _copy_from_user+0x2b/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] __blk_trace_setup+0x96/0x180 kernel/trace/blktrace.c:626 blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648 sg_ioctl_common drivers/scsi/sg.c:1114 [inline] sg_ioctl+0x65e/0x2720 drivers/scsi/sg.c:1156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (&q->debugfs_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x147/0x930 kernel/locking/mutex.c:752 blk_mq_init_sched+0x436/0x650 block/blk-mq-sched.c:473 elevator_init_mq+0x2cc/0x420 block/elevator.c:610 device_add_disk+0x10e/0x12f0 block/genhd.c:411 sd_probe+0xa0e/0xf80 drivers/scsi/sd.c:4024 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x24f/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1df/0x450 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830 __device_attach_driver+0x1db/0x2f0 drivers/base/dd.c:958 bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:459 __device_attach_async_helper+0x1d1/0x290 drivers/base/dd.c:987 async_run_entry_fn+0x9c/0x530 kernel/async.c:129 process_one_work+0xa02/0x1bf0 kernel/workqueue.c:3232 process_scheduled_works kernel/workqueue.c:3314 [inline] worker_thread+0x677/0xe90 kernel/workqueue.c:3395 kthread+0x2c7/0x3b0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #5 (&q->q_usage_counter(queue)#51){++++}-{0:0}: blk_queue_enter+0x4d0/0x600 block/blk-core.c:328 blk_mq_alloc_request+0x422/0x9c0 block/blk-mq.c:680 scsi_alloc_request drivers/scsi/scsi_lib.c:1227 [inline] scsi_execute_cmd+0x1fe/0xf20 drivers/scsi/scsi_lib.c:304 read_capacity_16+0x1f2/0xe60 drivers/scsi/sd.c:2655 sd_read_capacity drivers/scsi/sd.c:2824 [inline] sd_revalidate_disk.isra.0+0x1989/0xa440 drivers/scsi/sd.c:3734 sd_probe+0x887/0xf80 drivers/scsi/sd.c:4010 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x24f/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1df/0x450 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830 __device_attach_driver+0x1db/0x2f0 drivers/base/dd.c:958 bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:459 __device_attach_async_helper+0x1d1/0x290 drivers/base/dd.c:987 async_run_entry_fn+0x9c/0x530 kernel/async.c:129 process_one_work+0xa02/0x1bf0 kernel/workqueue.c:3232 process_scheduled_works kernel/workqueue.c:3314 [inline] worker_thread+0x677/0xe90 kernel/workqueue.c:3395 kthread+0x2c7/0x3b0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #4 (&q->limits_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x147/0x930 kernel/locking/mutex.c:752 queue_limits_start_update include/linux/blkdev.h:935 [inline] loop_reconfigure_limits+0x1f2/0x960 drivers/block/loop.c:1004 loop_set_block_size drivers/block/loop.c:1474 [inline] lo_simple_ioctl drivers/block/loop.c:1497 [inline] lo_ioctl+0xb92/0x1870 drivers/block/loop.c:1560 blkdev_ioctl+0x27b/0x6c0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (&q->q_usage_counter(io)#19){++++}-{0:0}: bio_queue_enter block/blk.h:76 [inline] blk_mq_submit_bio+0x2167/0x2b70 block/blk-mq.c:3090 __submit_bio+0x399/0x630 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:716 [inline] submit_bio_noacct_nocheck+0x6c3/0xd00 block/blk-core.c:745 submit_bio_noacct+0x57a/0x1fa0 block/blk-core.c:868 submit_bh fs/buffer.c:2824 [inline] __bread_slow fs/buffer.c:1270 [inline] __bread_gfp+0x189/0x340 fs/buffer.c:1494 sb_bread include/linux/buffer_head.h:346 [inline] read_block_bitmap fs/udf/balloc.c:43 [inline] load_block_bitmap+0x1ff/0x570 fs/udf/balloc.c:99 udf_bitmap_free_blocks fs/udf/balloc.c:150 [inline] udf_free_blocks+0x57c/0x10a0 fs/udf/balloc.c:674 udf_evict_inode+0x34c/0x590 fs/udf/inode.c:163 evict+0x3ef/0x940 fs/inode.c:725 iput_final fs/inode.c:1877 [inline] iput fs/inode.c:1903 [inline] iput+0x511/0x7f0 fs/inode.c:1889 do_unlinkat+0x58f/0x710 fs/namei.c:4540 __do_sys_unlink fs/namei.c:4581 [inline] __se_sys_unlink fs/namei.c:4579 [inline] __x64_sys_unlink+0xc7/0x110 fs/namei.c:4579 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&sbi->s_alloc_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x147/0x930 kernel/locking/mutex.c:752 udf_bitmap_new_block fs/udf/balloc.c:236 [inline] udf_new_block+0x7e2/0x1750 fs/udf/balloc.c:721 inode_getblk+0xe88/0x3bb0 fs/udf/inode.c:895 udf_map_block+0x2e3/0x5a0 fs/udf/inode.c:447 __udf_get_block+0x9c/0x340 fs/udf/inode.c:461 __block_write_begin_int+0x4e5/0x1670 fs/buffer.c:2121 block_write_begin+0x9a/0x1d0 fs/buffer.c:2231 udf_write_begin+0x1bc/0x280 fs/udf/inode.c:256 generic_perform_write+0x2bd/0x900 mm/filemap.c:4065 __generic_file_write_iter+0x1f6/0x240 mm/filemap.c:4166 udf_file_write_iter+0x233/0x740 fs/udf/file.c:111 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xbfc/0x10d0 fs/read_write.c:683 ksys_write+0x122/0x250 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&ei->i_data_sem#2){++++}-{3:3}: down_write+0x92/0x200 kernel/locking/rwsem.c:1577 udf_expand_file_adinicb+0x174/0x970 fs/udf/inode.c:363 udf_setsize+0x4b2/0x10f0 fs/udf/inode.c:1289 udf_setattr+0x523/0x6c0 fs/udf/file.c:236 notify_change+0x6d3/0x1280 fs/attr.c:503 do_truncate+0x143/0x200 fs/open.c:65 vfs_truncate+0x3e3/0x4c0 fs/open.c:111 do_sys_truncate.part.0+0xf7/0x140 fs/open.c:134 do_sys_truncate fs/open.c:128 [inline] __do_sys_truncate fs/open.c:146 [inline] __se_sys_truncate fs/open.c:144 [inline] __x64_sys_truncate+0x6d/0xa0 fs/open.c:144 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (mapping.invalidate_lock#4){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:870 [inline] udf_page_mkwrite+0x2af/0xa20 fs/udf/file.c:50 do_page_mkwrite+0x17d/0x390 mm/memory.c:3161 wp_page_shared mm/memory.c:3562 [inline] do_wp_page+0x1291/0x4860 mm/memory.c:3712 handle_pte_fault mm/memory.c:5786 [inline] __handle_mm_fault+0x150c/0x2a20 mm/memory.c:5913 handle_mm_fault+0x404/0xab0 mm/memory.c:6081 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
other info that might help us debug this:
Chain exists of: mapping.invalidate_lock#4 --> &vma->vm_lock->lock --> sb_pagefaults#2
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- rlock(sb_pagefaults#2); lock(&vma->vm_lock->lock); lock(sb_pagefaults#2); rlock(mapping.invalidate_lock#4);
*** DEADLOCK ***
2 locks held by syz.6.870/18445: #0: ffff888050dbed18 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline] #0: ffff888050dbed18 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x141/0x9a0 mm/memory.c:6247 #1: ffff888044124518 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x17d/0x390 mm/memory.c:3161
stack backtrace: CPU: 0 UID: 0 PID: 18445 Comm: syz.6.870 Not tainted 6.12.24 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_circular_bug+0x406/0x5c0 kernel/locking/lockdep.c:2074 check_noncircular+0x2f7/0x3e0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:870 [inline] udf_page_mkwrite+0x2af/0xa20 fs/udf/file.c:50 do_page_mkwrite+0x17d/0x390 mm/memory.c:3161 wp_page_shared mm/memory.c:3562 [inline] do_wp_page+0x1291/0x4860 mm/memory.c:3712 handle_pte_fault mm/memory.c:5786 [inline] __handle_mm_fault+0x150c/0x2a20 mm/memory.c:5913 handle_mm_fault+0x404/0xab0 mm/memory.c:6081 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fc9b0c4f002 Code: f0 48 8b 54 24 f0 8b 8a 80 00 00 00 8b 82 04 01 00 00 21 c8 83 c1 01 c1 e0 04 48 8b b4 02 40 01 00 00 48 8b 84 02 48 01 00 00 <89> 8a 80 00 00 00 48 81 fe 45 23 01 00 74 09 48 81 fe 56 34 02 00 RSP: 002b:00007fc9b1c9af88 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00007fc9b0fe6080 RCX: 0000000000000001 RDX: 0000200000ff9000 RSI: 0000000000000000 RDI: 0000200000ff9000 RBP: 00007fc9b0e46d56 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000ff9000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc9b0fe6080 R15: 00007fc9b1c7b000 </TASK>
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I hope it helps. Best regards Jianzhou Zhao