Hello, syzbot found the following issue on:
HEAD commit: d7fa1af5b33e Merge branch 'for-next/core' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=125f1170580000 kernel config: https://syzkaller.appspot.com/x/.config?x=89c13de706fbf07a dashboard link: https://syzkaller.appspot.com/bug?extid=4784e928cc299a6dd040 compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/da97ad659b2c/disk-d7fa1af5.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/659e123552a8/vmlinux-d7fa1af5.xz kernel image: https://storage.googleapis.com/syzbot-assets/6ec5dbf4643e/Image-d7fa1af5.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4784e928cc299a6dd...@syzkaller.appspotmail.com XFS (loop4): Ending clean mount ====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 Not tainted ------------------------------------------------------ syz.4.374/8650 is trying to acquire lock: ffff0000d13456d0 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0x9c/0x124 mm/memory.c:7150 but task is already holding lock: ffff0000c9ae65d0 (&dev->mode_config.idr_mutex){+.+.}-{4:4}, at: drm_mode_get_lease_ioctl+0x1c8/0x53c drivers/gpu/drm/drm_lease.c:660 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&dev->mode_config.idr_mutex){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2190 kernel/locking/mutex.c:601 __mutex_lock kernel/locking/mutex.c:746 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:798 __drm_mode_object_add+0xa8/0x1f0 drivers/gpu/drm/drm_mode_object.c:47 drm_framebuffer_init+0x14c/0x2bc drivers/gpu/drm/drm_framebuffer.c:875 drm_gem_fb_init drivers/gpu/drm/drm_gem_framebuffer_helper.c:82 [inline] drm_gem_fb_init_with_funcs+0xa60/0xda4 drivers/gpu/drm/drm_gem_framebuffer_helper.c:202 drm_gem_fb_create_with_funcs drivers/gpu/drm/drm_gem_framebuffer_helper.c:245 [inline] drm_gem_fb_create+0x84/0xd4 drivers/gpu/drm/drm_gem_framebuffer_helper.c:286 drm_internal_framebuffer_create+0xfcc/0x19dc drivers/gpu/drm/drm_framebuffer.c:304 drm_mode_addfb2+0xac/0x2a0 drivers/gpu/drm/drm_framebuffer.c:338 drm_client_buffer_addfb drivers/gpu/drm/drm_client.c:386 [inline] drm_client_framebuffer_create+0x2d0/0x55c drivers/gpu/drm/drm_client.c:428 drm_fbdev_shmem_driver_fbdev_probe+0x180/0x70c drivers/gpu/drm/drm_fbdev_shmem.c:151 drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1649 [inline] __drm_fb_helper_initial_config_and_unlock+0xf94/0x159c drivers/gpu/drm/drm_fb_helper.c:1829 drm_fb_helper_initial_config+0x3c/0x58 drivers/gpu/drm/drm_fb_helper.c:1916 drm_fbdev_client_hotplug+0x154/0x22c drivers/gpu/drm/clients/drm_fbdev_client.c:52 drm_client_register+0x13c/0x1d4 drivers/gpu/drm/drm_client.c:140 drm_fbdev_client_setup+0x194/0x3d0 drivers/gpu/drm/clients/drm_fbdev_client.c:159 drm_client_setup+0x78/0x140 drivers/gpu/drm/clients/drm_client_setup.c:39 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:218 [inline] vkms_init+0x4b8/0x5ac drivers/gpu/drm/vkms/vkms_drv.c:242 do_one_initcall+0x250/0x990 init/main.c:1257 do_initcall_level+0x154/0x214 init/main.c:1319 do_initcalls+0x84/0xf4 init/main.c:1335 do_basic_setup+0x8c/0xa0 init/main.c:1354 kernel_init_freeable+0x2dc/0x444 init/main.c:1567 kernel_init+0x24/0x1dc init/main.c:1457 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847 -> #4 (&helper->lock){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2190 kernel/locking/mutex.c:601 __mutex_lock kernel/locking/mutex.c:746 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:798 __drm_fb_helper_restore_fbdev_mode_unlocked+0x74/0x198 drivers/gpu/drm/drm_fb_helper.c:228 drm_fb_helper_set_par+0xa4/0x108 drivers/gpu/drm/drm_fb_helper.c:1359 fbcon_init+0xe4c/0x1d18 drivers/video/fbdev/core/fbcon.c:1112 visual_init+0x27c/0x540 drivers/tty/vt/vt.c:1011 do_bind_con_driver+0x7b8/0xdd8 drivers/tty/vt/vt.c:3831 do_take_over_console+0x824/0x97c drivers/tty/vt/vt.c:4397 do_fbcon_takeover+0x158/0x25c drivers/video/fbdev/core/fbcon.c:548 do_fb_registered drivers/video/fbdev/core/fbcon.c:2989 [inline] fbcon_fb_registered+0x354/0x4c8 drivers/video/fbdev/core/fbcon.c:3009 do_register_framebuffer drivers/video/fbdev/core/fbmem.c:449 [inline] register_framebuffer+0x44c/0x5ec drivers/video/fbdev/core/fbmem.c:515 __drm_fb_helper_initial_config_and_unlock+0x103c/0x159c drivers/gpu/drm/drm_fb_helper.c:1851 drm_fb_helper_initial_config+0x3c/0x58 drivers/gpu/drm/drm_fb_helper.c:1916 drm_fbdev_client_hotplug+0x154/0x22c drivers/gpu/drm/clients/drm_fbdev_client.c:52 drm_client_register+0x13c/0x1d4 drivers/gpu/drm/drm_client.c:140 drm_fbdev_client_setup+0x194/0x3d0 drivers/gpu/drm/clients/drm_fbdev_client.c:159 drm_client_setup+0x78/0x140 drivers/gpu/drm/clients/drm_client_setup.c:39 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:218 [inline] vkms_init+0x4b8/0x5ac drivers/gpu/drm/vkms/vkms_drv.c:242 do_one_initcall+0x250/0x990 init/main.c:1257 do_initcall_level+0x154/0x214 init/main.c:1319 do_initcalls+0x84/0xf4 init/main.c:1335 do_basic_setup+0x8c/0xa0 init/main.c:1354 kernel_init_freeable+0x2dc/0x444 init/main.c:1567 kernel_init+0x24/0x1dc init/main.c:1457 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847 -> #3 (console_lock){+.+.}-{0:0}: console_lock+0x194/0x1ec kernel/printk/printk.c:2849 __bch2_print_string_as_lines fs/bcachefs/util.c:267 [inline] bch2_print_string_as_lines+0x34/0x150 fs/bcachefs/util.c:286 bucket_ref_update_err+0x1c8/0x21c fs/bcachefs/buckets.c:417 bch2_bucket_ref_update+0x3d8/0x888 fs/bcachefs/buckets.c:-1 __mark_pointer fs/bcachefs/buckets.c:572 [inline] bch2_trigger_pointer fs/bcachefs/buckets.c:618 [inline] __trigger_extent+0xd90/0x35fc fs/bcachefs/buckets.c:763 bch2_trigger_extent+0x3e4/0x78c fs/bcachefs/buckets.c:881 run_one_trans_trigger fs/bcachefs/btree_trans_commit.c:-1 [inline] bch2_trans_commit_run_triggers fs/bcachefs/btree_trans_commit.c:550 [inline] __bch2_trans_commit+0x7e8/0x62d0 fs/bcachefs/btree_trans_commit.c:990 bch2_trans_commit fs/bcachefs/btree_update.h:195 [inline] bch2_extent_update+0x2d8/0x7e8 fs/bcachefs/io_write.c:353 bch2_fpunch_at+0x4dc/0x98c fs/bcachefs/io_misc.c:187 __bch2_resume_logged_op_truncate+0x340/0x4b4 fs/bcachefs/io_misc.c:265 bch2_truncate+0x144/0x1e4 fs/bcachefs/io_misc.c:300 bchfs_truncate+0x648/0xa70 fs/bcachefs/fs-io.c:509 bch2_setattr+0x198/0x20c fs/bcachefs/fs.c:1245 notify_change+0x9a4/0xc50 fs/attr.c:552 do_truncate+0x178/0x1f0 fs/open.c:65 handle_truncate fs/namei.c:3501 [inline] do_open fs/namei.c:3884 [inline] path_openat+0x25a0/0x2c40 fs/namei.c:4039 do_filp_open+0x18c/0x36c fs/namei.c:4066 do_sys_openat2+0x11c/0x1b4 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __arm64_sys_openat+0x120/0x158 fs/open.c:1455 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 -> #2 (bcachefs_btree){+.+.}-{0:0}: trans_set_locked+0x94/0x200 fs/bcachefs/btree_locking.h:198 bch2_trans_begin+0x6f8/0xa40 fs/bcachefs/btree_iter.c:3288 bch2_read_err_msg_trans+0x64/0x298 fs/bcachefs/io_read.c:346 __bch2_read_extent+0x21fc/0x3694 fs/bcachefs/io_read.c:975 bch2_read_extent fs/bcachefs/io_read.h:140 [inline] bchfs_read+0x1178/0x17dc fs/bcachefs/fs-io-buffered.c:226 bch2_readahead+0xa18/0xd88 fs/bcachefs/fs-io-buffered.c:316 read_pages+0x13c/0x4c8 mm/readahead.c:160 page_cache_ra_order+0x7b8/0xb34 mm/readahead.c:515 do_sync_mmap_readahead+0x2f0/0x660 mm/filemap.c:-1 filemap_fault+0x600/0x1278 mm/filemap.c:3403 bch2_page_fault+0x2cc/0x700 fs/bcachefs/fs-io-pagecache.c:594 __do_fault+0xf8/0x498 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 mm/memory.c:5997 [inline] __handle_mm_fault mm/memory.c:6140 [inline] handle_mm_fault+0x2cb0/0x4d18 mm/memory.c:6309 faultin_page mm/gup.c:1193 [inline] __get_user_pages+0x1dd4/0x30d8 mm/gup.c:1491 populate_vma_page_range+0x218/0x2e8 mm/gup.c:1929 __mm_populate+0x208/0x330 mm/gup.c:2032 mm_populate include/linux/mm.h:3487 [inline] vm_mmap_pgoff+0x378/0x43c mm/util.c:584 ksys_mmap_pgoff+0x394/0x5b8 mm/mmap.c:607 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 -> #1 (mapping.invalidate_lock#4){.+.+}-{4:4}: down_read+0x58/0x2f8 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:922 [inline] filemap_fault+0x564/0x1278 mm/filemap.c:3391 bch2_page_fault+0x2cc/0x700 fs/bcachefs/fs-io-pagecache.c:594 __do_fault+0xf8/0x498 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 mm/memory.c:5997 [inline] __handle_mm_fault mm/memory.c:6140 [inline] handle_mm_fault+0x2cb0/0x4d18 mm/memory.c:6309 faultin_page mm/gup.c:1193 [inline] __get_user_pages+0x1dd4/0x30d8 mm/gup.c:1491 populate_vma_page_range+0x218/0x2e8 mm/gup.c:1929 __mm_populate+0x208/0x330 mm/gup.c:2032 mm_populate include/linux/mm.h:3487 [inline] vm_mmap_pgoff+0x378/0x43c mm/util.c:584 ksys_mmap_pgoff+0x394/0x5b8 mm/mmap.c:607 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 -> #0 (&mm->mmap_lock){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1728/0x3058 kernel/locking/lockdep.c:5235 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5866 __might_fault+0xc4/0x124 mm/memory.c:7151 drm_mode_get_lease_ioctl+0x2bc/0x53c drivers/gpu/drm/drm_lease.c:673 drm_ioctl_kernel+0x238/0x310 drivers/gpu/drm/drm_ioctl.c:796 drm_ioctl+0x65c/0xa5c 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 fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 other info that might help us debug this: Chain exists of: &mm->mmap_lock --> &helper->lock --> &dev->mode_config.idr_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&dev->mode_config.idr_mutex); lock(&helper->lock); lock(&dev->mode_config.idr_mutex); rlock(&mm->mmap_lock); *** DEADLOCK *** 1 lock held by syz.4.374/8650: #0: ffff0000c9ae65d0 (&dev->mode_config.idr_mutex){+.+.}-{4:4}, at: drm_mode_get_lease_ioctl+0x1c8/0x53c drivers/gpu/drm/drm_lease.c:660 stack backtrace: CPU: 0 UID: 0 PID: 8650 Comm: syz.4.374 Not tainted 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2079 check_noncircular+0x154/0x174 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 kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1728/0x3058 kernel/locking/lockdep.c:5235 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5866 __might_fault+0xc4/0x124 mm/memory.c:7151 drm_mode_get_lease_ioctl+0x2bc/0x53c drivers/gpu/drm/drm_lease.c:673 drm_ioctl_kernel+0x238/0x310 drivers/gpu/drm/drm_ioctl.c:796 drm_ioctl+0x65c/0xa5c 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 fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 netlink: 60 bytes leftover after parsing attributes in process `syz.4.374'. netlink: 72 bytes leftover after parsing attributes in process `syz.4.374'. --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkal...@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
