syzbot

======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-00404-g8560697b23dc #0 Not tainted
------------------------------------------------------
syz.3.963/9602 is trying to acquire lock:
ffff88807da14140 (bcachefs_btree){+.+.}-{0:0}, at: trans_set_locked fs/bcachefs/btree_locking.h:198 [inline]
ffff88807da14140 (bcachefs_btree){+.+.}-{0:0}, at: bch2_trans_begin+0x9cc/0x1d30 fs/bcachefs/btree_iter.c:3279

but task is already holding lock:
ffff88805785a8e0 (mapping.invalidate_lock#16){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:922 [inline]
ffff88805785a8e0 (mapping.invalidate_lock#16){.+.+}-{4:4}, at: page_cache_ra_order+0x45e/0xca0 mm/readahead.c:491

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #9 (mapping.invalidate_lock#16){.+.+}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       down_read+0xb3/0xa50 kernel/locking/rwsem.c:1524
       filemap_invalidate_lock_shared include/linux/fs.h:922 [inline]
       filemap_fault+0x66b/0x13d0 mm/filemap.c:3391
       bch2_page_fault+0x52e/0x960 fs/bcachefs/fs-io-pagecache.c:594
       __do_fault+0x137/0x390 mm/memory.c:5098
       do_shared_fault mm/memory.c:5582 [inline]
       do_fault mm/memory.c:5656 [inline]
       do_pte_missing mm/memory.c:4160 [inline]
       handle_pte_fault+0xfcc/0x61c0 mm/memory.c:5997
       __handle_mm_fault mm/memory.c:6140 [inline]
       handle_mm_fault+0x1129/0x1bf0 mm/memory.c:6309
       do_user_addr_fault arch/x86/mm/fault.c:1337 [inline]
       handle_page_fault arch/x86/mm/fault.c:1480 [inline]
       exc_page_fault+0x45b/0x920 arch/x86/mm/fault.c:1538
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #8 (vm_lock){++++}-{0:0}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __vma_enter_locked+0x238/0x4a0 mm/memory.c:6473
       __vma_start_write+0x1f/0x120 mm/memory.c:6497
       vma_start_write include/linux/mm.h:829 [inline]
       mprotect_fixup+0x5f0/0xa40 mm/mprotect.c:670
       setup_arg_pages+0x5e4/0xb60 fs/exec.c:780
       load_elf_binary+0xbc6/0x28a0 fs/binfmt_elf.c:1019
       search_binary_handler fs/exec.c:1778 [inline]
       exec_binprm fs/exec.c:1810 [inline]
       bprm_execve+0x9ab/0x1430 fs/exec.c:1862
       kernel_execve+0x92e/0xa50 fs/exec.c:2028
       try_to_run_init_process init/main.c:1385 [inline]
       kernel_init+0xed/0x2b0 init/main.c:1513
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #7 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __might_fault+0xc6/0x120 mm/memory.c:7151
       drm_mode_atomic_ioctl+0x5d8/0x1420 drivers/gpu/drm/drm_atomic_uapi.c:1458
       drm_ioctl_kernel+0x350/0x450 drivers/gpu/drm/drm_ioctl.c:796
       drm_ioctl+0x687/0xbb0 drivers/gpu/drm/drm_ioctl.c:893
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (crtc_ww_class_mutex){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       ww_acquire_init include/linux/ww_mutex.h:162 [inline]
       drm_modeset_acquire_init+0x20b/0x3d0 drivers/gpu/drm/drm_modeset_lock.c:250
       drmm_mode_config_init+0xe06/0x1800 drivers/gpu/drm/drm_mode_config.c:462
       vkms_modeset_init drivers/gpu/drm/vkms/vkms_drv.c:146 [inline]
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:207 [inline]
       vkms_init+0x387/0x770 drivers/gpu/drm/vkms/vkms_drv.c:242
       do_one_initcall+0x24c/0x940 init/main.c:1257
       do_initcall_level+0x157/0x210 init/main.c:1319
       do_initcalls+0x71/0xd0 init/main.c:1335
       kernel_init_freeable+0x432/0x5d0 init/main.c:1567
       kernel_init+0x1d/0x2b0 init/main.c:1457
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #5 (crtc_ww_class_acquire){+.+.}-{0:0}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       ww_acquire_init include/linux/ww_mutex.h:161 [inline]
       drm_modeset_acquire_init+0x1ee/0x3d0 drivers/gpu/drm/drm_modeset_lock.c:250
       drm_client_modeset_commit_atomic+0xd1/0x7d0 drivers/gpu/drm/drm_client_modeset.c:1018
       drm_client_modeset_commit_locked+0xe0/0x520 drivers/gpu/drm/drm_client_modeset.c:1182
       drm_client_modeset_commit+0x4a/0x70 drivers/gpu/drm/drm_client_modeset.c:1208
       __drm_fb_helper_restore_fbdev_mode_unlocked+0xbd/0x200 drivers/gpu/drm/drm_fb_helper.c:237
       drm_fb_helper_set_par+0xaf/0x100 drivers/gpu/drm/drm_fb_helper.c:1359
       fbcon_init+0x112d/0x2100 drivers/video/fbdev/core/fbcon.c:1112
       visual_init+0x2e9/0x660 drivers/tty/vt/vt.c:1011
       do_bind_con_driver+0x869/0xf70 drivers/tty/vt/vt.c:3831
       do_take_over_console+0x5e7/0x750 drivers/tty/vt/vt.c:4397
       do_fbcon_takeover+0x11a/0x200 drivers/video/fbdev/core/fbcon.c:548
       do_fb_registered drivers/video/fbdev/core/fbcon.c:2989 [inline]
       fbcon_fb_registered+0x364/0x620 drivers/video/fbdev/core/fbcon.c:3009
       do_register_framebuffer drivers/video/fbdev/core/fbmem.c:449 [inline]
       register_framebuffer+0x65f/0x820 drivers/video/fbdev/core/fbmem.c:515
       __drm_fb_helper_initial_config_and_unlock+0x1624/0x1cf0 drivers/gpu/drm/drm_fb_helper.c:1851
       drm_fbdev_client_hotplug+0x16e/0x230 drivers/gpu/drm/clients/drm_fbdev_client.c:52
       drm_client_register+0x181/0x210 drivers/gpu/drm/drm_client.c:140
       drm_fbdev_client_setup+0x1a9/0x3f0 drivers/gpu/drm/clients/drm_fbdev_client.c:159
       drm_client_setup+0x60/0x120 drivers/gpu/drm/clients/drm_client_setup.c:39
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:218 [inline]
       vkms_init+0x610/0x770 drivers/gpu/drm/vkms/vkms_drv.c:242
       do_one_initcall+0x24c/0x940 init/main.c:1257
       do_initcall_level+0x157/0x210 init/main.c:1319
       do_initcalls+0x71/0xd0 init/main.c:1335
       kernel_init_freeable+0x432/0x5d0 init/main.c:1567
       kernel_init+0x1d/0x2b0 init/main.c:1457
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #4 (&client->modeset_mutex){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       drm_client_modeset_probe+0x3b8/0x5380 drivers/gpu/drm/drm_client_modeset.c:843
       __drm_fb_helper_initial_config_and_unlock+0x11d/0x1cf0 drivers/gpu/drm/drm_fb_helper.c:1828
       drm_fbdev_client_hotplug+0x16e/0x230 drivers/gpu/drm/clients/drm_fbdev_client.c:52
       drm_client_register+0x181/0x210 drivers/gpu/drm/drm_client.c:140
       drm_fbdev_client_setup+0x1a9/0x3f0 drivers/gpu/drm/clients/drm_fbdev_client.c:159
       drm_client_setup+0x60/0x120 drivers/gpu/drm/clients/drm_client_setup.c:39
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:218 [inline]
       vkms_init+0x610/0x770 drivers/gpu/drm/vkms/vkms_drv.c:242
       do_one_initcall+0x24c/0x940 init/main.c:1257
       do_initcall_level+0x157/0x210 init/main.c:1319
       do_initcalls+0x71/0xd0 init/main.c:1335
       kernel_init_freeable+0x432/0x5d0 init/main.c:1567
       kernel_init+0x1d/0x2b0 init/main.c:1457
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (&helper->lock){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       __drm_fb_helper_restore_fbdev_mode_unlocked+0x9c/0x200 drivers/gpu/drm/drm_fb_helper.c:228
       drm_fb_helper_set_par+0xaf/0x100 drivers/gpu/drm/drm_fb_helper.c:1359
       fbcon_init+0x112d/0x2100 drivers/video/fbdev/core/fbcon.c:1112
       visual_init+0x2e9/0x660 drivers/tty/vt/vt.c:1011
       do_bind_con_driver+0x869/0xf70 drivers/tty/vt/vt.c:3831
       do_take_over_console+0x5e7/0x750 drivers/tty/vt/vt.c:4397
       do_fbcon_takeover+0x11a/0x200 drivers/video/fbdev/core/fbcon.c:548
       do_fb_registered drivers/video/fbdev/core/fbcon.c:2989 [inline]
       fbcon_fb_registered+0x364/0x620 drivers/video/fbdev/core/fbcon.c:3009
       do_register_framebuffer drivers/video/fbdev/core/fbmem.c:449 [inline]
       register_framebuffer+0x65f/0x820 drivers/video/fbdev/core/fbmem.c:515
       __drm_fb_helper_initial_config_and_unlock+0x1624/0x1cf0 drivers/gpu/drm/drm_fb_helper.c:1851
       drm_fbdev_client_hotplug+0x16e/0x230 drivers/gpu/drm/clients/drm_fbdev_client.c:52
       drm_client_register+0x181/0x210 drivers/gpu/drm/drm_client.c:140
       drm_fbdev_client_setup+0x1a9/0x3f0 drivers/gpu/drm/clients/drm_fbdev_client.c:159
       drm_client_setup+0x60/0x120 drivers/gpu/drm/clients/drm_client_setup.c:39
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:218 [inline]
       vkms_init+0x610/0x770 drivers/gpu/drm/vkms/vkms_drv.c:242
       do_one_initcall+0x24c/0x940 init/main.c:1257
       do_initcall_level+0x157/0x210 init/main.c:1319
       do_initcalls+0x71/0xd0 init/main.c:1335
       kernel_init_freeable+0x432/0x5d0 init/main.c:1567
       kernel_init+0x1d/0x2b0 init/main.c:1457
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (console_lock){+.+.}-{0:0}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       console_lock+0x164/0x1b0 kernel/printk/printk.c:2849
       __bch2_print_string_as_lines fs/bcachefs/util.c:267 [inline]
       bch2_print_string_as_lines+0x2d/0x140 fs/bcachefs/util.c:286
       __bch2_fsck_err+0xed7/0x14d0 fs/bcachefs/error.c:563
       __btree_err+0x60b/0x710 fs/bcachefs/btree_io.c:587
       validate_bset_keys+0x5e1/0x1b00 fs/bcachefs/btree_io.c:928
       bch2_btree_node_read_done+0x2343/0x6290 fs/bcachefs/btree_io.c:1166
       btree_node_read_work+0x6cb/0x1400 fs/bcachefs/btree_io.c:1366
       bch2_btree_node_read+0x2427/0x29e0 fs/bcachefs/btree_io.c:-1
       __bch2_btree_root_read fs/bcachefs/btree_io.c:1797 [inline]
       bch2_btree_root_read+0x656/0x7e0 fs/bcachefs/btree_io.c:1819
       read_btree_roots+0x3d7/0xa80 fs/bcachefs/recovery.c:581
       bch2_fs_recovery+0x28e4/0x3e20 fs/bcachefs/recovery.c:928
       bch2_fs_start+0x310/0x620 fs/bcachefs/super.c:1065
       bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
       vfs_get_tree+0x92/0x2b0 fs/super.c:1759
       do_new_mount+0x2cf/0xb70 fs/namespace.c:3881
       do_mount fs/namespace.c:4221 [inline]
       __do_sys_mount fs/namespace.c:4432 [inline]
       __se_sys_mount+0x38c/0x400 fs/namespace.c:4409
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&c->fsck_error_msgs_lock){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       __bch2_fsck_err+0x415/0x14d0 fs/bcachefs/error.c:458
       bch2_btree_repair_topology_recurse+0x133b/0x6ba0 fs/bcachefs/btree_gc.c:352
       bch2_check_topology+0x932/0xe40 fs/bcachefs/btree_gc.c:554
       bch2_run_recovery_pass+0xf2/0x1e0 fs/bcachefs/recovery_passes.c:226
       bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:285
       bch2_fs_recovery+0x292a/0x3e20 fs/bcachefs/recovery.c:936
       bch2_fs_start+0x310/0x620 fs/bcachefs/super.c:1065
       bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
       vfs_get_tree+0x92/0x2b0 fs/super.c:1759
       do_new_mount+0x2cf/0xb70 fs/namespace.c:3881
       do_mount fs/namespace.c:4221 [inline]
       __do_sys_mount fs/namespace.c:4432 [inline]
       __se_sys_mount+0x38c/0x400 fs/namespace.c:4409
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (bcachefs_btree){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       trans_set_locked fs/bcachefs/btree_locking.h:198 [inline]
       bch2_trans_begin+0x9e1/0x1d30 fs/bcachefs/btree_iter.c:3279
       bchfs_read+0x1ad/0x3320 fs/bcachefs/fs-io-buffered.c:169
       bch2_readahead+0xe7a/0x12d0 fs/bcachefs/fs-io-buffered.c:316
       read_pages+0x195/0x590 mm/readahead.c:160
       page_cache_ra_order+0xa37/0xca0 mm/readahead.c:515
       do_sync_mmap_readahead+0x3e6/0x6c0 mm/filemap.c:-1
       filemap_fault+0x763/0x13d0 mm/filemap.c:3403
       bch2_page_fault+0x52e/0x960 fs/bcachefs/fs-io-pagecache.c:594
       __do_fault+0x137/0x390 mm/memory.c:5098
       do_read_fault mm/memory.c:5518 [inline]
       do_fault mm/memory.c:5652 [inline]
       do_pte_missing mm/memory.c:4160 [inline]
       handle_pte_fault+0x3f0c/0x61c0 mm/memory.c:5997
       __handle_mm_fault mm/memory.c:6140 [inline]
       handle_mm_fault+0x1129/0x1bf0 mm/memory.c:6309
       faultin_page mm/gup.c:1193 [inline]
       __get_user_pages+0x1adc/0x4180 mm/gup.c:1491
       populate_vma_page_range+0x266/0x340 mm/gup.c:1929
       __mm_populate+0x27d/0x460 mm/gup.c:2032
       mm_populate include/linux/mm.h:3470 [inline]
       vm_mmap_pgoff+0x390/0x530 mm/util.c:584
       ksys_mmap_pgoff+0x4ee/0x720 mm/mmap.c:607
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  bcachefs_btree --> vm_lock --> mapping.invalidate_lock#16

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(mapping.invalidate_lock#16);
                               lock(vm_lock);
                               lock(mapping.invalidate_lock#16);
  lock(bcachefs_btree);

 *** DEADLOCK ***

1 lock held by syz.3.963/9602:
 #0: ffff88805785a8e0 (mapping.invalidate_lock#16){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:922 [inline]
 #0: ffff88805785a8e0 (mapping.invalidate_lock#16){.+.+}-{4:4}, at: page_cache_ra_order+0x45e/0xca0 mm/readahead.c:491

stack backtrace:
CPU: 0 UID: 0 PID: 9602 Comm: syz.3.963 Not tainted 6.15.0-rc2-syzkaller-00404-g8560697b23dc #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 trans_set_locked fs/bcachefs/btree_locking.h:198 [inline]
 bch2_trans_begin+0x9e1/0x1d30 fs/bcachefs/btree_iter.c:3279
 bchfs_read+0x1ad/0x3320 fs/bcachefs/fs-io-buffered.c:169
 bch2_readahead+0xe7a/0x12d0 fs/bcachefs/fs-io-buffered.c:316
 read_pages+0x195/0x590 mm/readahead.c:160
 page_cache_ra_order+0xa37/0xca0 mm/readahead.c:515
 do_sync_mmap_readahead+0x3e6/0x6c0 mm/filemap.c:-1
 filemap_fault+0x763/0x13d0 mm/filemap.c:3403
 bch2_page_fault+0x52e/0x960 fs/bcachefs/fs-io-pagecache.c:594
 __do_fault+0x137/0x390 mm/memory.c:5098
 do_read_fault mm/memory.c:5518 [inline]
 do_fault mm/memory.c:5652 [inline]
 do_pte_missing mm/memory.c:4160 [inline]
 handle_pte_fault+0x3f0c/0x61c0 mm/memory.c:5997
 __handle_mm_fault mm/memory.c:6140 [inline]
 handle_mm_fault+0x1129/0x1bf0 mm/memory.c:6309
 faultin_page mm/gup.c:1193 [inline]
 __get_user_pages+0x1adc/0x4180 mm/gup.c:1491
 populate_vma_page_range+0x266/0x340 mm/gup.c:1929
 __mm_populate+0x27d/0x460 mm/gup.c:2032
 mm_populate include/linux/mm.h:3470 [inline]
 vm_mmap_pgoff+0x390/0x530 mm/util.c:584
 ksys_mmap_pgoff+0x4ee/0x720 mm/mmap.c:607
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff70538e169
Code: ff ff c3 66 2e 0f 1f 84 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 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff706153038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ff7055b5fa0 RCX: 00007ff70538e169
RDX: 00000000007ffff7 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007ff705410a68 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff7055b5fa0 R15: 00007ffefce7a848
 </TASK>