Hi folks, Byungchul, Gwan-gyeong and I are investigating possible circular dependency reported by a dependency tracker named DEPT [1], which is able to report possible circular dependencies involving folio locks and other forms of dependencies that are not locks (i.e., wait for completion). Below are two similar reports from DEPT where one context takes i_data_sem and then folio lock in ext4_map_blocks(), while the other context takes folio lock and then i_data_sem during processing of pwrite64() system calls. We're reaching out due to a lack of understanding of ext4 and file system internals. The points in question are: - Can the two contexts actually create a dependency between each other in ext4? In other words, do their uses of folio lock make them belong to the same lock classes? - Are there any locking rules in ext4 that ensure these two contexts will never be considered as the same lock class? Best, Hyeonggon ==== Report 1: Possible circular dependency between fsync() and pwrite64() ==== [ 402.888557] =================================================== [ 402.888967] DEPT: Circular dependency has been detected. [ 402.888967] 6.9.0-rc7 #145 Not tainted [ 402.888967] --------------------------------------------------- [ 402.888967] summary [ 402.888967] --------------------------------------------------- [ 402.888967] *** DEADLOCK *** [ 402.888967] [ 402.888967] context A [ 402.888967] [S] lock(&ei->i_data_sem:0) [ 402.888967] [W] dept_page_wait_on_bit(PG_locked_map:0) [ 402.888967] [E] unlock(&ei->i_data_sem:0) [ 402.888967] [ 402.888967] context B [ 402.888967] [S] (event requestor)(PG_locked_map:0) [ 402.888967] [W] lock(&ei->i_data_sem:0) [ 402.888967] [E] dept_page_clear_bit(PG_locked_map:0) [ 402.888967] [ 402.888967] [S]: start of the event context [ 402.888967] [W]: the wait blocked [ 402.888967] [E]: the event not reachable [ 402.888967] --------------------------------------------------- [ 402.888967] context A's detail [ 402.888967] --------------------------------------------------- [ 402.888967] context A [ 402.888967] [S] lock(&ei->i_data_sem:0) [ 402.888967] [W] dept_page_wait_on_bit(PG_locked_map:0) [ 402.888967] [E] unlock(&ei->i_data_sem:0) [ 402.888967] [ 402.888967] [S] lock(&ei->i_data_sem:0): [ 402.888967] ext4_map_blocks (fs/ext4/ext4.h:1936 fs/ext4/inode.c:622) [ 402.888967] stacktrace: [ 402.888967] ext4_map_blocks (fs/ext4/ext4.h:1936 fs/ext4/inode.c:622) [ 402.888967] ext4_do_writepages (fs/ext4/inode.c:2164 fs/ext4/inode.c:2216 fs/ext4/inode.c:2679) [ 402.888967] ext4_writepages (fs/ext4/inode.c:2768) [ 402.888967] do_writepages (mm/page-writeback.c:2619) [ 402.888967] __filemap_fdatawrite_range (mm/filemap.c:431) [ 402.888967] file_write_and_wait_range (mm/filemap.c:789) [ 402.888967] ext4_sync_file (fs/ext4/fsync.c:158) [ 402.888967] __x64_sys_fsync (./include/linux/file.h:47 fs/sync.c:213 fs/sync.c:220 fs/sync.c:218 fs/sync.c:218) [ 402.888967] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 402.888967] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 402.888967] [ 402.888967] [W] dept_page_wait_on_bit(PG_locked_map:0): [ 402.888967] __filemap_get_folio (./include/linux/pagemap.h:1054 ./include/linux/pagemap.h:1049 mm/filemap.c:1900) [ 402.888967] stacktrace: [ 402.888967] folio_wait_bit_common (./include/linux/page-flags.h:873 mm/filemap.c:1224) [ 402.888967] __filemap_get_folio (./include/linux/pagemap.h:1054 ./include/linux/pagemap.h:1049 mm/filemap.c:1900) [ 402.888967] pagecache_get_page (mm/folio-compat.c:94) [ 402.888967] ext4_mb_load_buddy_gfp (./include/linux/pagemap.h:757 fs/ext4/mballoc.c:1634) [ 402.888967] ext4_mb_regular_allocator (fs/ext4/mballoc.c:2898) [ 402.888967] ext4_mb_new_blocks (fs/ext4/mballoc.c:6205) [ 402.888967] ext4_ext_map_blocks (fs/ext4/extents.c:4317) [ 402.888967] ext4_map_blocks (fs/ext4/inode.c:623) [ 402.888967] ext4_do_writepages (fs/ext4/inode.c:2164 fs/ext4/inode.c:2216 fs/ext4/inode.c:2679) [ 402.888967] ext4_writepages (fs/ext4/inode.c:2768) [ 402.888967] do_writepages (mm/page-writeback.c:2619) [ 402.888967] __filemap_fdatawrite_range (mm/filemap.c:431) [ 402.888967] file_write_and_wait_range (mm/filemap.c:789) [ 402.888967] ext4_sync_file (fs/ext4/fsync.c:158) [ 402.888967] __x64_sys_fsync (./include/linux/file.h:47 fs/sync.c:213 fs/sync.c:220 fs/sync.c:218 fs/sync.c:218) [ 402.888967] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 402.888967] [ 402.888967] [E] unlock(&ei->i_data_sem:0): [ 402.888967] (N/A) [ 402.888967] --------------------------------------------------- [ 402.888967] context B's detail [ 402.888967] --------------------------------------------------- [ 402.888967] context B [ 402.888967] [S] (event requestor)(PG_locked_map:0) [ 402.888967] [W] lock(&ei->i_data_sem:0) [ 402.888967] [E] dept_page_clear_bit(PG_locked_map:0) [ 402.888967] [ 402.888967] [S] (event requestor)(PG_locked_map:0): [ 402.888967] stacktrace: [ 402.888967] filemap_add_folio (mm/filemap.c:948) [ 402.888967] __filemap_get_folio (mm/filemap.c:1960) [ 402.888967] ext4_da_write_begin (fs/ext4/inode.c:2885) [ 402.888967] generic_perform_write (mm/filemap.c:4000) [ 402.888967] ext4_buffered_write_iter (./include/linux/fs.h:800 fs/ext4/file.c:302) [ 402.888967] ext4_file_write_iter (fs/ext4/file.c:698) [ 402.888967] vfs_write (./include/linux/fs.h:2110 fs/read_write.c:497 fs/read_write.c:590) [ 402.888967] __x64_sys_pwrite64 (fs/read_write.c:705 fs/read_write.c:715 fs/read_write.c:712 fs/read_write.c:712) [ 402.888967] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 402.888967] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 402.888967] [ 402.888967] [W] lock(&ei->i_data_sem:0): [ 402.888967] ext4_da_get_block_prep (fs/ext4/ext4.h:1936 fs/ext4/ext4.h:3600 fs/ext4/inode.c:1745 fs/ext4/inode.c:1817) [ 402.888967] stacktrace: [ 402.888967] ext4_da_get_block_prep (fs/ext4/ext4.h:1936 fs/ext4/ext4.h:3600 fs/ext4/inode.c:1745 fs/ext4/inode.c:1817) [ 402.888967] __block_write_begin_int (fs/buffer.c:2108) [ 402.888967] ext4_da_write_begin (fs/ext4/inode.c:2896) [ 402.888967] generic_perform_write (mm/filemap.c:4000) [ 402.888967] ext4_buffered_write_iter (./include/linux/fs.h:800 fs/ext4/file.c:302) [ 402.888967] ext4_file_write_iter (fs/ext4/file.c:698) [ 402.888967] vfs_write (./include/linux/fs.h:2110 fs/read_write.c:497 fs/read_write.c:590) [ 402.888967] __x64_sys_pwrite64 (fs/read_write.c:705 fs/read_write.c:715 fs/read_write.c:712 fs/read_write.c:712) [ 402.888967] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 402.888967] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 402.888967] [ 402.888967] [E] dept_page_clear_bit(PG_locked_map:0): [ 402.888967] ext4_da_write_end (./include/linux/instrumented.h:68 ./include/linux/atomic/atomic-instrumented.h:32 ./include/linux/page_ref.h:67 ./include/linux/mm.h:1134 ./include/linux/mm.h:1140 ./include/linux/mm.h:1507 fs/ext4/inode.c:2986 fs/ext4/inode.c:3028) [ 402.888967] stacktrace: [ 402.888967] folio_unlock (./include/linux/page-flags.h:858 (discriminator 2) mm/filemap.c:1510 (discriminator 2)) [ 402.888967] ext4_da_write_end (./include/linux/instrumented.h:68 ./include/linux/atomic/atomic-instrumented.h:32 ./include/linux/page_ref.h:67 ./include/linux/mm.h:1134 ./include/linux/mm.h:1140 ./include/linux/mm.h:1507 fs/ext4/inode.c:2986 fs/ext4/inode.c:3028) [ 402.888967] generic_perform_write (mm/filemap.c:4011) [ 402.888967] ext4_buffered_write_iter (./include/linux/fs.h:800 fs/ext4/file.c:302) [ 402.888967] ext4_file_write_iter (fs/ext4/file.c:698) [ 402.888967] vfs_write (./include/linux/fs.h:2110 fs/read_write.c:497 fs/read_write.c:590) [ 402.888967] __x64_sys_pwrite64 (fs/read_write.c:705 fs/read_write.c:715 fs/read_write.c:712 fs/read_write.c:712) [ 402.888967] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 402.888967] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 402.888967] --------------------------------------------------- [ 402.888967] information that might be helpful [ 402.888967] --------------------------------------------------- [ 402.888967] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 402.888967] Call Trace: [ 402.888967] <TASK> [ 402.888967] dump_stack_lvl (lib/dump_stack.c:118) [ 402.888967] print_circle (./include/linux/instrumented.h:96 ./include/linux/atomic/atomic-instrumented.h:592 kernel/dependency/dept.c:149 kernel/dependency/dept.c:886) [ 402.888967] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) [ 402.888967] ? extend_queue (./include/linux/list.h:150 ./include/linux/list.h:183 kernel/dependency/dept.c:898 kernel/dependency/dept.c:927) [ 402.888967] cb_check_dl (kernel/dependency/dept.c:1244) [ 402.888967] bfs (kernel/dependency/dept.c:984) [ 402.888967] ? __pfx_cb_check_dl (kernel/dependency/dept.c:1220) [ 402.888967] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) [ 402.888967] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 402.888967] ? mark_lock (kernel/locking/lockdep.c:4666) [ 402.888967] ? __pfx_bfs (kernel/dependency/dept.c:954) [ 402.888967] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 402.888967] ? __add_dep (./include/linux/list.h:150 ./include/linux/list.h:169 kernel/dependency/dept.c:1214) [ 402.888967] add_dep (kernel/dependency/dept.c:1579) [ 402.888967] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) [ 402.888967] ? __pfx_add_dep (kernel/dependency/dept.c:1560) [ 402.888967] ? __pfx_from_pool (kernel/dependency/dept.c:351) [ 402.888967] ? __pfx_mark_lock (kernel/locking/lockdep.c:4649) [ 402.888967] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) [ 402.888967] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 402.888967] __dept_wait (kernel/dependency/dept.c:1641 kernel/dependency/dept.c:2381) [ 402.888967] ? __filemap_get_folio (./include/linux/pagemap.h:1054 ./include/linux/pagemap.h:1049 mm/filemap.c:1900) [ 402.888967] ? __pfx___lock_acquire (kernel/locking/lockdep.c:5005) [ 402.888967] ? __lock_acquire (kernel/locking/lockdep.c:5146 (discriminator 9)) [ 402.888967] ? __pfx___dept_wait (kernel/dependency/dept.c:2359) [ 402.888967] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 402.888967] ? lock_acquire (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5776 kernel/locking/lockdep.c:5739) [ 402.888967] ? __filemap_get_folio (./include/linux/pagemap.h:1054 ./include/linux/pagemap.h:1049 mm/filemap.c:1900) [ 403.025017] dept_wait (kernel/dependency/dept.c:2446) [ 403.025017] folio_wait_bit_common (./include/linux/page-flags.h:873 mm/filemap.c:1224) [ 403.025017] ? __pfx_folio_wait_bit_common (mm/filemap.c:1212) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? filemap_get_entry (mm/filemap.c:1835) [ 403.025017] ? __pfx_filemap_get_entry (mm/filemap.c:1835) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? lock_is_held_type (kernel/locking/lockdep.c:5507 kernel/locking/lockdep.c:5845) [ 403.025017] __filemap_get_folio (./include/linux/pagemap.h:1054 ./include/linux/pagemap.h:1049 mm/filemap.c:1900) [ 403.025017] pagecache_get_page (mm/folio-compat.c:94) [ 403.025017] ext4_mb_load_buddy_gfp (./include/linux/pagemap.h:757 fs/ext4/mballoc.c:1634) [ 403.025017] ext4_mb_regular_allocator (fs/ext4/mballoc.c:2898) [ 403.025017] ? __pfx_ext4_mb_regular_allocator (fs/ext4/mballoc.c:2786) [ 403.025017] ? ext4_mb_normalize_request.constprop.0 (fs/ext4/mballoc.c:4540) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? __kasan_slab_alloc (mm/kasan/common.c:341) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? kmem_cache_alloc (mm/slub.c:3858) [ 403.025017] ext4_mb_new_blocks (fs/ext4/mballoc.c:6205) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 mm/kasan/common.c:69) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? __kasan_kmalloc (mm/kasan/common.c:391) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? __kmalloc (mm/slub.c:3980) [ 403.025017] ? __pfx_ext4_mb_new_blocks (fs/ext4/mballoc.c:6126) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? ext4_find_extent (fs/ext4/extents.c:815 fs/ext4/extents.c:953) [ 403.025017] ext4_ext_map_blocks (fs/ext4/extents.c:4317) [ 403.025017] ? __is_insn_slot_addr (kernel/kprobes.c:312) [ 403.025017] ? __pfx___lock_acquire (kernel/locking/lockdep.c:5005) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? __kernel_text_address (kernel/extable.c:79) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? unwind_get_return_address (arch/x86/kernel/unwind_orc.c:369 arch/x86/kernel/unwind_orc.c:364) [ 403.025017] ? __pfx_stack_trace_consume_entry (kernel/stacktrace.c:83) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:26) [ 403.025017] ? __pfx_ext4_ext_map_blocks (fs/ext4/extents.c:4128) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? ext4_map_blocks (fs/ext4/ext4.h:1936 fs/ext4/inode.c:622) [ 403.025017] ? __pfx_lock_acquire (kernel/locking/lockdep.c:5742) [ 403.025017] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.025017] ? stack_trace_save (kernel/stacktrace.c:123) [ 403.045075] ? __pfx_stack_trace_save (kernel/stacktrace.c:114) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? dept_ecxt_enter (kernel/dependency/dept.c:2768 (discriminator 1)) [ 403.045075] ? __pfx_down_write (kernel/locking/rwsem.c:1577) [ 403.045075] ? ext4_es_lookup_extent (./include/trace/events/ext4.h:2313 fs/ext4/extents_status.c:1047) [ 403.045075] ext4_map_blocks (fs/ext4/inode.c:623) [ 403.045075] ? __pfx_ext4_map_blocks (fs/ext4/inode.c:481) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? __kasan_slab_alloc (mm/kasan/common.c:341) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? ext4_alloc_io_end_vec (fs/ext4/page-io.c:61) [ 403.045075] ext4_do_writepages (fs/ext4/inode.c:2164 fs/ext4/inode.c:2216 fs/ext4/inode.c:2679) [ 403.045075] ? __pfx_ext4_do_writepages (fs/ext4/inode.c:2512) [ 403.045075] ? stack_trace_save (kernel/stacktrace.c:123) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? dept_ecxt_enter (kernel/dependency/dept.c:2768 (discriminator 1)) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? lock_is_held_type (kernel/locking/lockdep.c:5507 kernel/locking/lockdep.c:5845) [ 403.045075] ext4_writepages (fs/ext4/inode.c:2768) [ 403.045075] ? __pfx_ext4_writepages (fs/ext4/inode.c:2754) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? ext4_buffered_write_iter (fs/ext4/file.c:303) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? lock_release (kernel/locking/lockdep.c:5442 kernel/locking/lockdep.c:5794) [ 403.045075] do_writepages (mm/page-writeback.c:2619) [ 403.045075] ? dept_ecxt_exit (kernel/dependency/dept.c:2948) [ 403.045075] ? __pfx_do_writepages (mm/page-writeback.c:2602) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? up_write (./arch/x86/include/asm/atomic64_64.h:91 ./include/linux/atomic/atomic-arch-fallback.h:2852 ./include/linux/atomic/atomic-long.h:268 ./include/linux/atomic/atomic-instrumented.h:3391 kernel/locking/rwsem.c:1374 kernel/locking/rwsem.c:1632) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? llist_add_batch (lib/llist.c:33 (discriminator 14)) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? llist_add_batch (lib/llist.c:33 (discriminator 14)) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] ? __lock_acquire (kernel/locking/lockdep.c:5146 (discriminator 9)) [ 403.045075] __filemap_fdatawrite_range (mm/filemap.c:431) [ 403.045075] ? __pfx___filemap_fdatawrite_range (mm/filemap.c:423) [ 403.045075] file_write_and_wait_range (mm/filemap.c:789) [ 403.045075] ext4_sync_file (fs/ext4/fsync.c:158) [ 403.045075] ? srso_return_thunk (arch/x86/lib/retpoline.S:224) [ 403.045075] __x64_sys_fsync (./include/linux/file.h:47 fs/sync.c:213 fs/sync.c:220 fs/sync.c:218 fs/sync.c:218) [ 403.045075] do_syscall_64 (arch/x86/entry/common.c:53 arch/x86/entry/common.c:85) [ 403.045075] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 403.045075] RIP: 0033:0x7f93ccae65eb [ 403.045075] RSP: 002b:00007f93c1dfde50 EFLAGS: 00000293 ORIG_RAX: 000000000000004a [ 403.045075] RAX: ffffffffffffffda RBX: 00000000003e0000 RCX: 00007f93ccae65eb [ 403.045075] RDX: 000055f93c6e639d RSI: 00007f93c1dfde70 RDI: 0000000000000014 [ 403.045075] RBP: 00007f93c1dffebc R08: 0000000000000000 R09: 00007f93c1dfde70 [ 403.045075] R10: 0000000000000180 R11: 0000000000000293 R12: 0000000000000014 [ 403.045075] R13: 00007f93c1dfde70 R14: 000055f93c702004 R15: 0000000000802000 [ 403.045075] </TASK> ==== Report 2: Possible circular dependency between mkdir() and pwrite64() [ 19.908810] DEPT: Circular dependency has been detected. [ 19.908810] 6.9.0-rc7 #52 Not tainted [ 19.908810] --------------------------------------------------- [ 19.908810] summary [ 19.908810] --------------------------------------------------- [ 19.908810] *** DEADLOCK *** [ 19.908810] [ 19.908810] context A [ 19.908810] [S] lock(&ei->i_data_sem:0) [ 19.908810] [W] dept_page_wait_on_bit(PG_locked_map:0) [ 19.908810] [E] unlock(&ei->i_data_sem:0) [ 19.908810] [ 19.908810] context B [ 19.908810] [S] (event requestor)(PG_locked_map:0) [ 19.908810] [W] lock(&ei->i_data_sem:0) [ 19.908810] [E] dept_page_clear_bit(PG_locked_map:0) [ 19.908810] [ 19.908810] [S]: start of the event context [ 19.908810] [W]: the wait blocked [ 19.908810] [E]: the event not reachable [ 19.908810] --------------------------------------------------- [ 19.908810] context A's detail [ 19.908810] --------------------------------------------------- [ 19.908810] context A [ 19.908810] [S] lock(&ei->i_data_sem:0) [ 19.908810] [W] dept_page_wait_on_bit(PG_locked_map:0) [ 19.908810] [E] unlock(&ei->i_data_sem:0) [ 19.908810] [ 19.908810] [S] lock(&ei->i_data_sem:0): [ 19.908810] [<ffffffffa83e460d>] ext4_map_blocks+0x20d/0x5f0 [ 19.908810] stacktrace: [ 19.908810] ext4_map_blocks+0x20d/0x5f0 [ 19.908810] ext4_getblk+0x7a/0x2e0 [ 19.908810] ext4_bread+0xb/0x70 [ 19.908810] ext4_append+0x88/0x190 [ 19.908810] ext4_init_new_dir+0xd6/0x180 [ 19.908810] ext4_mkdir+0x19d/0x340 [ 19.908810] vfs_mkdir+0x151/0x230 [ 19.908810] do_mkdirat+0x85/0x130 [ 19.908810] __x64_sys_mkdir+0x46/0x70 [ 19.908810] do_syscall_64+0xc8/0x1d0 [ 19.908810] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 19.908810] [ 19.908810] [W] dept_page_wait_on_bit(PG_locked_map:0): [ 19.908810] [<ffffffffa823de44>] __filemap_get_folio+0x1f4/0x240 [ 19.908810] stacktrace: [ 19.908810] folio_wait_bit_common+0x289/0x360 [ 19.908810] __filemap_get_folio+0x1f4/0x240 [ 19.908810] pagecache_get_page+0xd/0x40 [ 19.908810] ext4_mb_init_group+0x73/0x320 [ 19.908810] ext4_mb_prefetch_fini+0x7d/0xa0 [ 19.908810] ext4_mb_regular_allocator+0x4c0/0xde0 [ 19.908810] ext4_mb_new_blocks+0xa04/0x10d0 [ 19.908810] ext4_ind_map_blocks+0x7e5/0xbb0 [ 19.908810] ext4_map_blocks+0x2da/0x5f0 [ 19.908810] ext4_getblk+0x7a/0x2e0 [ 19.908810] ext4_bread+0xb/0x70 [ 19.908810] ext4_append+0x88/0x190 [ 19.908810] ext4_init_new_dir+0xd6/0x180 [ 19.908810] ext4_mkdir+0x19d/0x340 [ 19.908810] vfs_mkdir+0x151/0x230 [ 19.908810] do_mkdirat+0x85/0x130 [ 19.908810] [ 19.908810] [E] unlock(&ei->i_data_sem:0): [ 19.908810] (N/A) [ 19.908810] --------------------------------------------------- [ 19.908810] context B's detail [ 19.908810] --------------------------------------------------- [ 19.908810] context B [ 19.908810] [S] (event requestor)(PG_locked_map:0) [ 19.908810] [W] lock(&ei->i_data_sem:0) [ 19.908810] [E] dept_page_clear_bit(PG_locked_map:0) [ 19.908810] [ 19.908810] [S] (event requestor)(PG_locked_map:0): [ 19.908810] stacktrace: [ 19.908810] __filemap_get_folio+0xdf/0x240 [ 19.908810] ext4_da_write_begin+0xf1/0x2b0 [ 19.908810] generic_perform_write+0xca/0x210 [ 19.908810] ext4_buffered_write_iter+0x5d/0xe0 [ 19.908810] vfs_write+0x3d3/0x580 [ 19.908810] __x64_sys_pwrite64+0x92/0xc0 [ 19.908810] do_syscall_64+0xc8/0x1d0 [ 19.908810] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 19.908810] [ 19.908810] [W] lock(&ei->i_data_sem:0): [ 19.908810] [<ffffffffa83e31d9>] ext4_da_get_block_prep+0x1b9/0x400 [ 19.908810] stacktrace: [ 19.908810] ext4_da_get_block_prep+0x1b9/0x400 [ 19.908810] __block_write_begin_int+0x155/0x570 [ 19.908810] ext4_da_write_begin+0x11d/0x2b0 [ 19.908810] generic_perform_write+0xca/0x210 [ 19.908810] ext4_buffered_write_iter+0x5d/0xe0 [ 19.908810] vfs_write+0x3d3/0x580 [ 19.908810] __x64_sys_pwrite64+0x92/0xc0 [ 19.908810] do_syscall_64+0xc8/0x1d0 [ 19.908810] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 19.908810] [ 19.908810] [E] dept_page_clear_bit(PG_locked_map:0): [ 19.908810] [<ffffffffa83eb9bd>] ext4_da_write_end+0xbd/0x3b0 [ 19.908810] stacktrace: [ 19.908810] ext4_da_write_end+0xbd/0x3b0 [ 19.908810] generic_perform_write+0x11c/0x210 [ 19.908810] ext4_buffered_write_iter+0x5d/0xe0 [ 19.908810] vfs_write+0x3d3/0x580 [ 19.908810] __x64_sys_pwrite64+0x92/0xc0 [ 19.908810] do_syscall_64+0xc8/0x1d0 [ 19.908810] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 19.908810] --------------------------------------------------- [ 19.908810] information that might be helpful [ 19.908810] --------------------------------------------------- [ 19.908810] CPU: 0 PID: 378 Comm: mkdir Not tainted 6.9.0-rc7 #52 [ 19.908810] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 19.908810] Call Trace: [ 19.908810] <TASK> [ 19.908810] dump_stack_lvl+0x68/0xa0 [ 19.908810] print_circle+0x690/0x6b0 [ 19.908810] ? __pfx_cb_check_dl+0x10/0x10 [ 19.908810] cb_check_dl+0x5c/0x70 [ 19.908810] bfs+0xca/0x1a0 [ 19.908810] add_dep+0xaa/0x170 [ 19.908810] __dept_wait+0x1ef/0x580 [ 19.908810] ? __filemap_get_folio+0x1f4/0x240 [ 19.908810] dept_wait+0x9d/0xb0 [ 19.908810] ? __filemap_get_folio+0x1f4/0x240 [ 19.908810] folio_wait_bit_common+0x289/0x360 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ? filemap_get_entry+0x109/0x1e0 [ 19.908810] __filemap_get_folio+0x1f4/0x240 [ 19.908810] pagecache_get_page+0xd/0x40 [ 19.908810] ext4_mb_init_group+0x73/0x320 [ 19.908810] ext4_mb_prefetch_fini+0x7d/0xa0 [ 19.908810] ext4_mb_regular_allocator+0x4c0/0xde0 [ 19.908810] ? lock_release+0xbd/0x280 [ 19.908810] ? fs_reclaim_acquire+0x4e/0xf0 [ 19.908810] ext4_mb_new_blocks+0xa04/0x10d0 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ext4_ind_map_blocks+0x7e5/0xbb0 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ? lock_acquire+0xc0/0x2d0 [ 19.908810] ? ext4_map_blocks+0x20d/0x5f0 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ext4_map_blocks+0x2da/0x5f0 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ? lock_release+0xbd/0x280 [ 19.908810] ? srso_return_thunk+0x5/0x5f [ 19.908810] ext4_getblk+0x7a/0x2e0 [ 19.908810] ext4_bread+0xb/0x70 [ 19.908810] ext4_append+0x88/0x190 [ 19.908810] ext4_init_new_dir+0xd6/0x180 [ 19.908810] ext4_mkdir+0x19d/0x340 [ 19.908810] vfs_mkdir+0x151/0x230 [ 19.908810] do_mkdirat+0x85/0x130 [ 19.908810] __x64_sys_mkdir+0x46/0x70 [ 19.908810] do_syscall_64+0xc8/0x1d0 [ 19.908810] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 19.908810] RIP: 0033:0x7f4cbd4b4047 [ 19.908810] Code: 1f 40 00 48 8b 05 49 2e 0e 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 0000 00 00 00 66 90 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 19 2e 0e 00 f7 d8 64 89 01 48 [ 19.908810] RSP: 002b:00007fffa8322d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 [ 19.908810] RAX: ffffffffffffffda RBX: 000055947ace3c30 RCX: 00007f4cbd4b4047 [ 19.908810] RDX: 0000000000000000 RSI: 00000000000001ff RDI: 00007fffa8323e2d [ 19.908810] RBP: 00007fffa8323e20 R08: 0000000000000000 R09: 000055947ace3d60 [ 19.908810] R10: fffffffffffffd8c R11: 0000000000000246 R12: 00000000000001ff [ 19.908810] R13: 00007fffa8322ef0 R14: 00007fffa8323e2d R15: 0000000000000000 [ 19.908810] </TASK>
