syzbot


possible deadlock in __bch2_folio_reservation_get

Status: upstream: reported on 2024/11/26 00:01
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+9784eb115ca16c8cdd1d@syzkaller.appspotmail.com
First crash: 5d05h, last: 5d05h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] possible deadlock in __bch2_folio_reservation_get 0 (1) 2024/11/26 00:01

Sample crash report:
bcachefs (loop7): going read-write
bcachefs (loop7): done starting filesystem
======================================================
WARNING: possible circular locking dependency detected
6.12.0-syzkaller-03657-g43fb83c17ba2 #0 Not tainted
------------------------------------------------------
syz.7.1397/14121 is trying to acquire lock:
ffff88803c5049d0 (&c->mark_lock){++++}-{0:0}, at: bch2_disk_reservation_add fs/bcachefs/buckets.h:367 [inline]
ffff88803c5049d0 (&c->mark_lock){++++}-{0:0}, at: __bch2_folio_reservation_get+0x8d9/0xab0 fs/bcachefs/fs-io-pagecache.c:428

but task is already holding lock:
ffff88802940a518 (sb_pagefaults#5){.+.+}-{0:0}, at: do_page_mkwrite+0x17a/0x380 mm/memory.c:3162

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (sb_pagefaults#5){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1725 [inline]
       sb_start_pagefault include/linux/fs.h:1890 [inline]
       bch2_page_mkwrite+0x2ec/0xec0 fs/bcachefs/fs-io-pagecache.c:614
       do_page_mkwrite+0x17a/0x380 mm/memory.c:3162
       do_shared_fault mm/memory.c:5373 [inline]
       do_fault mm/memory.c:5435 [inline]
       do_pte_missing+0x29e/0x3e70 mm/memory.c:3965
       handle_pte_fault mm/memory.c:5766 [inline]
       __handle_mm_fault+0x100a/0x2a10 mm/memory.c:5909
       handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6077
       do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
       copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
       raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
       _inline_copy_to_user include/linux/uaccess.h:197 [inline]
       _copy_to_user+0xb6/0xd0 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:225 [inline]
       rng_dev_read+0x1f4/0x800 drivers/char/hw_random/core.c:258
       do_loop_readv_writev fs/read_write.c:840 [inline]
       do_loop_readv_writev fs/read_write.c:828 [inline]
       vfs_readv+0x6c2/0x890 fs/read_write.c:1013
       do_preadv+0x1b1/0x270 fs/read_write.c:1125
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault mm/memory.c:6716 [inline]
       __might_fault+0x11b/0x190 mm/memory.c:6709
       drm_mode_atomic_ioctl+0x524/0x25d0 drivers/gpu/drm/drm_atomic_uapi.c:1437
       drm_ioctl_kernel+0x1e9/0x3d0 drivers/gpu/drm/drm_ioctl.c:745
       drm_ioctl+0x5d6/0xc00 drivers/gpu/drm/drm_ioctl.c:842
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl fs/ioctl.c:892 [inline]
       __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (crtc_ww_class_mutex){+.+.}-{0:0}:
       ww_acquire_init include/linux/ww_mutex.h:162 [inline]
       drm_modeset_acquire_init+0x234/0x410 drivers/gpu/drm/drm_modeset_lock.c:250
       drmm_mode_config_init+0x10ef/0x1870 drivers/gpu/drm/drm_mode_config.c:453
       vkms_modeset_init drivers/gpu/drm/vkms/vkms_drv.c:156 [inline]
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:217 [inline]
       vkms_init+0x3bc/0x760 drivers/gpu/drm/vkms/vkms_drv.c:254
       do_one_initcall+0x12b/0x700 init/main.c:1266
       do_initcall_level init/main.c:1328 [inline]
       do_initcalls init/main.c:1344 [inline]
       do_basic_setup init/main.c:1363 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1577
       kernel_init+0x1c/0x2b0 init/main.c:1466
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #5 (crtc_ww_class_acquire){+.+.}-{0:0}:
       ww_acquire_init include/linux/ww_mutex.h:161 [inline]
       drm_modeset_acquire_init+0x219/0x410 drivers/gpu/drm/drm_modeset_lock.c:250
       drm_client_modeset_commit_atomic+0xc9/0x7f0 drivers/gpu/drm/drm_client_modeset.c:1007
       drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1171
       drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1197
       __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:237 [inline]
       __drm_fb_helper_restore_fbdev_mode_unlocked+0x130/0x180 drivers/gpu/drm/drm_fb_helper.c:216
       drm_fb_helper_set_par+0xd8/0x120 drivers/gpu/drm/drm_fb_helper.c:1345
       fbcon_init+0x883/0x1890 drivers/video/fbdev/core/fbcon.c:1113
       visual_init+0x320/0x620 drivers/tty/vt/vt.c:1011
       do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3833
       do_take_over_console+0x4f4/0x650 drivers/tty/vt/vt.c:4399
       do_fbcon_takeover+0xe8/0x210 drivers/video/fbdev/core/fbcon.c:549
       do_fb_registered drivers/video/fbdev/core/fbcon.c:2988 [inline]
       fbcon_fb_registered+0x375/0x6a0 drivers/video/fbdev/core/fbcon.c:3008
       do_register_framebuffer+0x466/0x7f0 drivers/video/fbdev/core/fbmem.c:449
       register_framebuffer+0x23/0x40 drivers/video/fbdev/core/fbmem.c:515
       __drm_fb_helper_initial_config_and_unlock+0xd56/0x1620 drivers/gpu/drm/drm_fb_helper.c:1869
       drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1934 [inline]
       drm_fb_helper_initial_config+0x44/0x60 drivers/gpu/drm/drm_fb_helper.c:1926
       drm_fbdev_shmem_client_hotplug+0x1a6/0x280 drivers/gpu/drm/drm_fbdev_shmem.c:250
       drm_client_register+0x198/0x280 drivers/gpu/drm/drm_client.c:141
       drm_fbdev_shmem_setup+0x184/0x340 drivers/gpu/drm/drm_fbdev_shmem.c:309
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:228 [inline]
       vkms_init+0x62d/0x760 drivers/gpu/drm/vkms/vkms_drv.c:254
       do_one_initcall+0x12b/0x700 init/main.c:1266
       do_initcall_level init/main.c:1328 [inline]
       do_initcalls init/main.c:1344 [inline]
       do_basic_setup init/main.c:1363 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1577
       kernel_init+0x1c/0x2b0 init/main.c:1466
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #4 (&client->modeset_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       drm_client_modeset_probe+0x41a/0x3060 drivers/gpu/drm/drm_client_modeset.c:832
       __drm_fb_helper_initial_config_and_unlock+0x131/0x1620 drivers/gpu/drm/drm_fb_helper.c:1846
       drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1934 [inline]
       drm_fb_helper_initial_config+0x44/0x60 drivers/gpu/drm/drm_fb_helper.c:1926
       drm_fbdev_shmem_client_hotplug+0x1a6/0x280 drivers/gpu/drm/drm_fbdev_shmem.c:250
       drm_client_register+0x198/0x280 drivers/gpu/drm/drm_client.c:141
       drm_fbdev_shmem_setup+0x184/0x340 drivers/gpu/drm/drm_fbdev_shmem.c:309
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:228 [inline]
       vkms_init+0x62d/0x760 drivers/gpu/drm/vkms/vkms_drv.c:254
       do_one_initcall+0x12b/0x700 init/main.c:1266
       do_initcall_level init/main.c:1328 [inline]
       do_initcalls init/main.c:1344 [inline]
       do_basic_setup init/main.c:1363 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1577
       kernel_init+0x1c/0x2b0 init/main.c:1466
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #3 (&helper->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:228 [inline]
       __drm_fb_helper_restore_fbdev_mode_unlocked+0xb6/0x180 drivers/gpu/drm/drm_fb_helper.c:216
       drm_fb_helper_set_par+0xd8/0x120 drivers/gpu/drm/drm_fb_helper.c:1345
       fbcon_init+0x883/0x1890 drivers/video/fbdev/core/fbcon.c:1113
       visual_init+0x320/0x620 drivers/tty/vt/vt.c:1011
       do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3833
       do_take_over_console+0x4f4/0x650 drivers/tty/vt/vt.c:4399
       do_fbcon_takeover+0xe8/0x210 drivers/video/fbdev/core/fbcon.c:549
       do_fb_registered drivers/video/fbdev/core/fbcon.c:2988 [inline]
       fbcon_fb_registered+0x375/0x6a0 drivers/video/fbdev/core/fbcon.c:3008
       do_register_framebuffer+0x466/0x7f0 drivers/video/fbdev/core/fbmem.c:449
       register_framebuffer+0x23/0x40 drivers/video/fbdev/core/fbmem.c:515
       __drm_fb_helper_initial_config_and_unlock+0xd56/0x1620 drivers/gpu/drm/drm_fb_helper.c:1869
       drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1934 [inline]
       drm_fb_helper_initial_config+0x44/0x60 drivers/gpu/drm/drm_fb_helper.c:1926
       drm_fbdev_shmem_client_hotplug+0x1a6/0x280 drivers/gpu/drm/drm_fbdev_shmem.c:250
       drm_client_register+0x198/0x280 drivers/gpu/drm/drm_client.c:141
       drm_fbdev_shmem_setup+0x184/0x340 drivers/gpu/drm/drm_fbdev_shmem.c:309
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:228 [inline]
       vkms_init+0x62d/0x760 drivers/gpu/drm/vkms/vkms_drv.c:254
       do_one_initcall+0x12b/0x700 init/main.c:1266
       do_initcall_level init/main.c:1328 [inline]
       do_initcalls init/main.c:1344 [inline]
       do_basic_setup init/main.c:1363 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1577
       kernel_init+0x1c/0x2b0 init/main.c:1466
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #2 (console_lock){+.+.}-{0:0}:
       console_lock+0x7a/0xa0 kernel/printk/printk.c:2833
       __bch2_print_string_as_lines+0xeb/0x130 fs/bcachefs/util.c:267
       __bch2_fsck_err+0x994/0x1d30 fs/bcachefs/error.c:411
       read_btree_roots fs/bcachefs/recovery.c:523 [inline]
       bch2_fs_recovery+0x2e46/0x4030 fs/bcachefs/recovery.c:853
       bch2_fs_start+0x2e9/0x5f0 fs/bcachefs/super.c:1037
       bch2_fs_get_tree+0x10db/0x16f0 fs/bcachefs/fs.c:2170
       vfs_get_tree+0x92/0x380 fs/super.c:1814
       do_new_mount fs/namespace.c:3507 [inline]
       path_mount+0x14e6/0x1f20 fs/namespace.c:3834
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount fs/namespace.c:4034 [inline]
       __x64_sys_mount+0x294/0x320 fs/namespace.c:4034
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&c->fsck_error_msgs_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       __bch2_fsck_err+0x34c/0x1d30 fs/bcachefs/error.c:282
       bch2_check_fix_ptr fs/bcachefs/buckets.c:137 [inline]
       bch2_check_fix_ptrs+0x1c1e/0x5230 fs/bcachefs/buckets.c:266
       bch2_trigger_extent+0x5d0/0x740 fs/bcachefs/buckets.c:856
       bch2_key_trigger fs/bcachefs/bkey_methods.h:87 [inline]
       bch2_gc_mark_key+0x546/0xe30 fs/bcachefs/btree_gc.c:634
       bch2_gc_btree.constprop.0+0xe5c/0x1320 fs/bcachefs/btree_gc.c:698
       bch2_gc_btrees+0x47c/0xa60 fs/bcachefs/btree_gc.c:729
       bch2_check_allocations+0x55a/0xa30 fs/bcachefs/btree_gc.c:1133
       bch2_run_recovery_pass+0x91/0x1a0 fs/bcachefs/recovery_passes.c:191
       bch2_run_recovery_passes+0x49b/0x780 fs/bcachefs/recovery_passes.c:244
       bch2_fs_recovery+0x2358/0x4030 fs/bcachefs/recovery.c:861
       bch2_fs_start+0x2e9/0x5f0 fs/bcachefs/super.c:1037
       bch2_fs_get_tree+0x10db/0x16f0 fs/bcachefs/fs.c:2170
       vfs_get_tree+0x92/0x380 fs/super.c:1814
       do_new_mount fs/namespace.c:3507 [inline]
       path_mount+0x14e6/0x1f20 fs/namespace.c:3834
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount fs/namespace.c:4034 [inline]
       __x64_sys_mount+0x294/0x320 fs/namespace.c:4034
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&c->mark_lock){++++}-{0:0}:
       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+0x249e/0x3c40 kernel/locking/lockdep.c:5226
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __bch2_disk_reservation_add+0xd2/0xd10 fs/bcachefs/buckets.c:1170
       bch2_disk_reservation_add fs/bcachefs/buckets.h:367 [inline]
       __bch2_folio_reservation_get+0x8d9/0xab0 fs/bcachefs/fs-io-pagecache.c:428
       bch2_folio_reservation_get fs/bcachefs/fs-io-pagecache.c:477 [inline]
       bch2_page_mkwrite+0xc4f/0xec0 fs/bcachefs/fs-io-pagecache.c:637
       do_page_mkwrite+0x17a/0x380 mm/memory.c:3162
       do_shared_fault mm/memory.c:5373 [inline]
       do_fault mm/memory.c:5435 [inline]
       do_pte_missing+0x29e/0x3e70 mm/memory.c:3965
       handle_pte_fault mm/memory.c:5766 [inline]
       __handle_mm_fault+0x100a/0x2a10 mm/memory.c:5909
       handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6077
       do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
       copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
       raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
       _inline_copy_to_user include/linux/uaccess.h:197 [inline]
       _copy_to_user+0xb6/0xd0 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:225 [inline]
       rng_dev_read+0x1f4/0x800 drivers/char/hw_random/core.c:258
       do_loop_readv_writev fs/read_write.c:840 [inline]
       do_loop_readv_writev fs/read_write.c:828 [inline]
       vfs_readv+0x6c2/0x890 fs/read_write.c:1013
       do_preadv+0x1b1/0x270 fs/read_write.c:1125
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &c->mark_lock --> &mm->mmap_lock --> sb_pagefaults#5

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_pagefaults#5);
                               lock(&mm->mmap_lock);
                               lock(sb_pagefaults#5);
  rlock(&c->mark_lock);

 *** DEADLOCK ***

2 locks held by syz.7.1397/14121:
 #0: ffff88807ec2c620 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
 #0: ffff88807ec2c620 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/memory.c:6114 [inline]
 #0: ffff88807ec2c620 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x35/0x6a0 mm/memory.c:6174
 #1: ffff88802940a518 (sb_pagefaults#5){.+.+}-{0:0}, at: do_page_mkwrite+0x17a/0x380 mm/memory.c:3162

stack backtrace:
CPU: 1 UID: 0 PID: 14121 Comm: syz.7.1397 Not tainted 6.12.0-syzkaller-03657-g43fb83c17ba2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
 check_noncircular+0x31a/0x400 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+0x249e/0x3c40 kernel/locking/lockdep.c:5226
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __bch2_disk_reservation_add+0xd2/0xd10 fs/bcachefs/buckets.c:1170
 bch2_disk_reservation_add fs/bcachefs/buckets.h:367 [inline]
 __bch2_folio_reservation_get+0x8d9/0xab0 fs/bcachefs/fs-io-pagecache.c:428
 bch2_folio_reservation_get fs/bcachefs/fs-io-pagecache.c:477 [inline]
 bch2_page_mkwrite+0xc4f/0xec0 fs/bcachefs/fs-io-pagecache.c:637
 do_page_mkwrite+0x17a/0x380 mm/memory.c:3162
 do_shared_fault mm/memory.c:5373 [inline]
 do_fault mm/memory.c:5435 [inline]
 do_pte_missing+0x29e/0x3e70 mm/memory.c:3965
 handle_pte_fault mm/memory.c:5766 [inline]
 __handle_mm_fault+0x100a/0x2a10 mm/memory.c:5909
 handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6077
 do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:197 [inline]
RIP: 0010:_copy_to_user+0xb6/0xd0 lib/usercopy.c:26
Code: 89 ee 48 89 ef e8 6a 05 fd fc 4d 85 ff 75 a8 e8 b0 03 fd fc 89 de 4c 89 e7 e8 76 24 5e fd 0f 01 cb 48 89 d9 48 89 ef 4c 89 e6 <f3> a4 0f 1f 00 0f 01 ca 48 89 cb eb 80 66 2e 0f 1f 84 00 00 00 00
RSP: 0018:ffffc90004d07b30 EFLAGS: 00050246
RAX: 0000000000000001 RBX: 0000000000000040 RCX: 0000000000000040
RDX: fffff520009a0f7f RSI: ffffc90004d07bb8 RDI: 000000002000b241
RBP: 000000002000b241 R08: 0000000000000000 R09: fffff520009a0f7e
R10: ffffc90004d07bf7 R11: 0000000000000000 R12: ffffc90004d07bb8
R13: 000000002000b281 R14: 00007fffffffefff R15: 0000000000000000
 copy_to_user include/linux/uaccess.h:225 [inline]
 rng_dev_read+0x1f4/0x800 drivers/char/hw_random/core.c:258
 do_loop_readv_writev fs/read_write.c:840 [inline]
 do_loop_readv_writev fs/read_write.c:828 [inline]
 vfs_readv+0x6c2/0x890 fs/read_write.c:1013
 do_preadv+0x1b1/0x270 fs/read_write.c:1125
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a1357e819
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:00007f3a143a6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f3a13735fa0 RCX: 00007f3a1357e819
RDX: 0000000000000001 RSI: 0000000020000580 RDI: 000000000000000b
RBP: 00007f3a135f175e R08: 0000000000000000 R09: 0000000000000000
R10: 00000000fffffff8 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3a13735fa0 R15: 00007fffd1526618
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 ee                	mov    %ebp,%esi
   2:	48 89 ef             	mov    %rbp,%rdi
   5:	e8 6a 05 fd fc       	call   0xfcfd0574
   a:	4d 85 ff             	test   %r15,%r15
   d:	75 a8                	jne    0xffffffb7
   f:	e8 b0 03 fd fc       	call   0xfcfd03c4
  14:	89 de                	mov    %ebx,%esi
  16:	4c 89 e7             	mov    %r12,%rdi
  19:	e8 76 24 5e fd       	call   0xfd5e2494
  1e:	0f 01 cb             	stac
  21:	48 89 d9             	mov    %rbx,%rcx
  24:	48 89 ef             	mov    %rbp,%rdi
  27:	4c 89 e6             	mov    %r12,%rsi
* 2a:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2c:	0f 1f 00             	nopl   (%rax)
  2f:	0f 01 ca             	clac
  32:	48 89 cb             	mov    %rcx,%rbx
  35:	eb 80                	jmp    0xffffffb7
  37:	66                   	data16
  38:	2e                   	cs
  39:	0f                   	.byte 0xf
  3a:	1f                   	(bad)
  3b:	84 00                	test   %al,(%rax)
  3d:	00 00                	add    %al,(%rax)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/21 18:23 upstream 43fb83c17ba2 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in __bch2_folio_reservation_get
* Struck through repros no longer work on HEAD.