Hello, syzbot found the following issue on: HEAD commit: bf152b0b41dc Merge tag 'for_linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10d32c14b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a845d34d07474 dashboard link: https://syzkaller.appspot.com/bug?extid=9738c8815b375ce482a1 userspace arch: arm Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9738c8815b375ce482a1@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 5.12.0-rc3-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor.0/4395 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ff78b3ec ( &(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq ){+.+.}-{0:0}, at: cgroup_rstat_flush_locked+0x424/0x624 kernel/cgroup/rstat.c:162 and this task is already holding: ddfc5a0c (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}-{2:2}, at: cgroup_rstat_flush_locked+0xa0/0x624 kernel/cgroup/rstat.c:153 which would create a new lock dependency: (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}-{2:2} -> (&(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq){+.+.}-{0:0} but this new dependency connects a HARDIRQ-irq-safe lock: (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}-{2:2} ... which became HARDIRQ-irq-safe at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x54/0x70 kernel/locking/spinlock.c:159 cgroup_rstat_updated+0x54/0xac kernel/cgroup/rstat.c:46 cgroup_base_stat_cputime_account_end+0x40/0x74 kernel/cgroup/rstat.c:354 __cgroup_account_cputime_field+0x54/0x70 kernel/cgroup/rstat.c:388 cgroup_account_cputime_field include/linux/cgroup.h:799 [inline] task_group_account_field+0x100/0x210 kernel/sched/cputime.c:110 account_system_index_time+0x88/0x94 kernel/sched/cputime.c:173 irqtime_account_process_tick+0x388/0x3b4 kernel/sched/cputime.c:390 account_process_tick+0x1ac/0x1f8 kernel/sched/cputime.c:477 update_process_times+0x64/0xcc kernel/time/timer.c:1794 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x84/0x3f4 kernel/time/tick-sched.c:1369 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x294/0x690 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x14c/0x2e0 kernel/time/hrtimer.c:1663 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline] arch_timer_handler_virt+0x30/0x38 drivers/clocksource/arm_arch_timer.c:658 handle_percpu_devid_irq+0xa4/0x19c kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] generic_handle_irq kernel/irq/irqdesc.c:652 [inline] __handle_domain_irq+0xb0/0x120 kernel/irq/irqdesc.c:689 handle_domain_irq include/linux/irqdesc.h:176 [inline] gic_handle_irq+0x84/0xac drivers/irqchip/irq-gic.c:370 __irq_svc+0x5c/0x94 arch/arm/kernel/entry-armv.S:205 arch_local_irq_enable arch/arm/include/asm/irqflags.h:39 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x2c/0x60 kernel/locking/spinlock.c:199 spin_unlock_irq include/linux/spinlock.h:404 [inline] cgroup_migrate_execute+0x250/0x4b8 kernel/cgroup/cgroup.c:2434 cgroup_migrate+0xec/0x15c kernel/cgroup/cgroup.c:2703 cgroup_attach_task+0x224/0x520 kernel/cgroup/cgroup.c:2736 __cgroup_procs_write+0xf0/0x1f0 kernel/cgroup/cgroup.c:4759 cgroup_procs_write+0x18/0x24 kernel/cgroup/cgroup.c:4772 cgroup_file_write+0xa4/0x26c kernel/cgroup/cgroup.c:3698 kernfs_fop_write_iter+0x128/0x1ec fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x260/0x350 fs/read_write.c:605 ksys_write+0x68/0xec fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] sys_write+0x10/0x14 fs/read_write.c:667 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x7e93d100 to a HARDIRQ-irq-unsafe lock: (&(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq){+.+.}-{0:0} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline] do_write_seqcount_begin include/linux/seqlock.h:545 [inline] u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline] blk_cgroup_bio_start+0x9c/0x174 block/blk-cgroup.c:1913 submit_bio_checks+0x200/0xad0 block/blk-core.c:893 submit_bio_noacct+0x28/0x3fc block/blk-core.c:1032 submit_bio+0x58/0x21c block/blk-core.c:1118 submit_bh_wbc+0x188/0x1b8 fs/buffer.c:3055 submit_bh fs/buffer.c:3061 [inline] block_read_full_page+0x520/0x624 fs/buffer.c:2340 blkdev_readpage+0x1c/0x20 fs/block_dev.c:640 do_read_cache_page+0x258/0x52c mm/filemap.c:3263 read_cache_page+0x1c/0x24 mm/filemap.c:3362 read_mapping_page include/linux/pagemap.h:500 [inline] read_part_sector+0x100/0x23c block/partitions/core.c:673 read_lba+0xb4/0x174 block/partitions/efi.c:250 find_valid_gpt block/partitions/efi.c:603 [inline] efi_partition+0x154/0xb5c block/partitions/efi.c:710 check_partition block/partitions/core.c:148 [inline] blk_add_partitions+0x148/0x82c block/partitions/core.c:610 bdev_disk_changed+0x13c/0x224 fs/block_dev.c:1268 __blkdev_get+0x2b0/0x334 fs/block_dev.c:1315 blkdev_get_by_dev fs/block_dev.c:1454 [inline] blkdev_get_by_dev+0x128/0x238 fs/block_dev.c:1422 disk_scan_partitions block/genhd.c:493 [inline] register_disk block/genhd.c:540 [inline] __device_add_disk+0x4e8/0x698 block/genhd.c:621 device_add_disk+0x14/0x18 block/genhd.c:639 add_disk include/linux/genhd.h:231 [inline] brd_init+0x148/0x1e0 drivers/block/brd.c:514 do_one_initcall+0x8c/0x59c init/main.c:1226 do_initcall_level init/main.c:1299 [inline] do_initcalls init/main.c:1315 [inline] do_basic_setup init/main.c:1335 [inline] kernel_init_freeable+0x2cc/0x330 init/main.c:1537 kernel_init+0x10/0x120 init/main.c:1424 ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158 0x0 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq); local_irq_disable(); lock(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); lock(&(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq); <Interrupt> lock(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); *** DEADLOCK *** 8 locks held by syz-executor.0/4395: #0: 859646c4 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x50/0x58 fs/file.c:961 #1: 857cd170 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x4c/0x5a8 fs/seq_file.c:179 #2: 86bb1a48 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x24/0xb4 fs/kernfs/file.c:112 #3: 86ad7dd8 (kn->active#57){.+.+}-{0:0}, at: kernfs_seq_start+0x2c/0xb4 fs/kernfs/file.c:113 #4: 82b10604 (cgroup_rstat_lock){....}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] #4: 82b10604 (cgroup_rstat_lock){....}-{2:2}, at: cgroup_rstat_flush_hold kernel/cgroup/rstat.c:228 [inline] #4: 82b10604 (cgroup_rstat_lock){....}-{2:2}, at: cgroup_base_stat_cputime_show+0x5c/0x1c4 kernel/cgroup/rstat.c:436 #5: ddfc5a0c (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}-{2:2}, at: cgroup_rstat_flush_locked+0xa0/0x624 kernel/cgroup/rstat.c:153 #6: 82b09c5c (rcu_read_lock){....}-{1:2}, at: cgroup_base_stat_add kernel/cgroup/rstat.c:301 [inline] #6: 82b09c5c (rcu_read_lock){....}-{1:2}, at: cgroup_base_stat_flush kernel/cgroup/rstat.c:336 [inline] #6: 82b09c5c (rcu_read_lock){....}-{1:2}, at: cgroup_rstat_flush_locked+0x3b4/0x624 kernel/cgroup/rstat.c:157 #7: 82b09c5c (rcu_read_lock){....}-{1:2}, at: blkcg_rstat_flush+0x0/0x61c block/blk-cgroup.c:946 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}-{2:2} { IN-HARDIRQ-W at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x54/0x70 kernel/locking/spinlock.c:159 cgroup_rstat_updated+0x54/0xac kernel/cgroup/rstat.c:46 cgroup_base_stat_cputime_account_end+0x40/0x74 kernel/cgroup/rstat.c:354 __cgroup_account_cputime_field+0x54/0x70 kernel/cgroup/rstat.c:388 cgroup_account_cputime_field include/linux/cgroup.h:799 [inline] task_group_account_field+0x100/0x210 kernel/sched/cputime.c:110 account_system_index_time+0x88/0x94 kernel/sched/cputime.c:173 irqtime_account_process_tick+0x388/0x3b4 kernel/sched/cputime.c:390 account_process_tick+0x1ac/0x1f8 kernel/sched/cputime.c:477 update_process_times+0x64/0xcc kernel/time/timer.c:1794 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x84/0x3f4 kernel/time/tick-sched.c:1369 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x294/0x690 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x14c/0x2e0 kernel/time/hrtimer.c:1663 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline] arch_timer_handler_virt+0x30/0x38 drivers/clocksource/arm_arch_timer.c:658 handle_percpu_devid_irq+0xa4/0x19c kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] generic_handle_irq kernel/irq/irqdesc.c:652 [inline] __handle_domain_irq+0xb0/0x120 kernel/irq/irqdesc.c:689 handle_domain_irq include/linux/irqdesc.h:176 [inline] gic_handle_irq+0x84/0xac drivers/irqchip/irq-gic.c:370 __irq_svc+0x5c/0x94 arch/arm/kernel/entry-armv.S:205 arch_local_irq_enable arch/arm/include/asm/irqflags.h:39 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x2c/0x60 kernel/locking/spinlock.c:199 spin_unlock_irq include/linux/spinlock.h:404 [inline] cgroup_migrate_execute+0x250/0x4b8 kernel/cgroup/cgroup.c:2434 cgroup_migrate+0xec/0x15c kernel/cgroup/cgroup.c:2703 cgroup_attach_task+0x224/0x520 kernel/cgroup/cgroup.c:2736 __cgroup_procs_write+0xf0/0x1f0 kernel/cgroup/cgroup.c:4759 cgroup_procs_write+0x18/0x24 kernel/cgroup/cgroup.c:4772 cgroup_file_write+0xa4/0x26c kernel/cgroup/cgroup.c:3698 kernfs_fop_write_iter+0x128/0x1ec fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x260/0x350 fs/read_write.c:605 ksys_write+0x68/0xec fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] sys_write+0x10/0x14 fs/read_write.c:667 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x7e93d100 INITIAL USE at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x54/0x70 kernel/locking/spinlock.c:159 cgroup_rstat_updated+0x54/0xac kernel/cgroup/rstat.c:46 cgroup_base_stat_cputime_account_end+0x40/0x74 kernel/cgroup/rstat.c:354 __cgroup_account_cputime_field+0x54/0x70 kernel/cgroup/rstat.c:388 cgroup_account_cputime_field include/linux/cgroup.h:799 [inline] task_group_account_field+0x100/0x210 kernel/sched/cputime.c:110 account_system_index_time+0x88/0x94 kernel/sched/cputime.c:173 irqtime_account_process_tick+0x388/0x3b4 kernel/sched/cputime.c:390 account_process_tick+0x1ac/0x1f8 kernel/sched/cputime.c:477 update_process_times+0x64/0xcc kernel/time/timer.c:1794 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x84/0x3f4 kernel/time/tick-sched.c:1369 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x294/0x690 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x14c/0x2e0 kernel/time/hrtimer.c:1663 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline] arch_timer_handler_virt+0x30/0x38 drivers/clocksource/arm_arch_timer.c:658 handle_percpu_devid_irq+0xa4/0x19c kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] generic_handle_irq kernel/irq/irqdesc.c:652 [inline] __handle_domain_irq+0xb0/0x120 kernel/irq/irqdesc.c:689 handle_domain_irq include/linux/irqdesc.h:176 [inline] gic_handle_irq+0x84/0xac drivers/irqchip/irq-gic.c:370 __irq_svc+0x5c/0x94 arch/arm/kernel/entry-armv.S:205 arch_local_irq_enable arch/arm/include/asm/irqflags.h:39 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x2c/0x60 kernel/locking/spinlock.c:199 spin_unlock_irq include/linux/spinlock.h:404 [inline] cgroup_migrate_execute+0x250/0x4b8 kernel/cgroup/cgroup.c:2434 cgroup_migrate+0xec/0x15c kernel/cgroup/cgroup.c:2703 cgroup_attach_task+0x224/0x520 kernel/cgroup/cgroup.c:2736 __cgroup_procs_write+0xf0/0x1f0 kernel/cgroup/cgroup.c:4759 cgroup_procs_write+0x18/0x24 kernel/cgroup/cgroup.c:4772 cgroup_file_write+0xa4/0x26c kernel/cgroup/cgroup.c:3698 kernfs_fop_write_iter+0x128/0x1ec fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x260/0x350 fs/read_write.c:605 ksys_write+0x68/0xec fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] sys_write+0x10/0x14 fs/read_write.c:667 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x7e93d100 } ... key at: [<832bcebc>] __key.0+0x0/0x8 ... acquired at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] __u64_stats_fetch_begin include/linux/u64_stats_sync.h:165 [inline] u64_stats_fetch_begin include/linux/u64_stats_sync.h:176 [inline] blkcg_rstat_flush+0xfc/0x61c block/blk-cgroup.c:777 cgroup_rstat_flush_locked+0x424/0x624 kernel/cgroup/rstat.c:162 cgroup_rstat_flush_hold kernel/cgroup/rstat.c:229 [inline] cgroup_base_stat_cputime_show+0x68/0x1c4 kernel/cgroup/rstat.c:436 cpu_stat_show+0x48/0x4b4 kernel/cgroup/cgroup.c:3532 cgroup_seqfile_show+0x50/0xc4 kernel/cgroup/cgroup.c:3759 kernfs_seq_show+0x2c/0x30 fs/kernfs/file.c:168 seq_read_iter+0x1c4/0x5a8 fs/seq_file.c:227 kernfs_fop_read_iter+0x138/0x1a8 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:1971 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x214/0x33c fs/read_write.c:496 ksys_read+0x68/0xec fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] sys_read+0x10/0x14 fs/read_write.c:642 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x76ff0038 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (&(&({ do { const void *__vpp_verify = (typeof((blkg->iostat_cpu) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))); (typeof((typeof(*((blkg->iostat_cpu))) *)((blkg->iostat_cpu)))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->sync)->seq){+.+.}-{0:0} { HARDIRQ-ON-W at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline] do_write_seqcount_begin include/linux/seqlock.h:545 [inline] u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline] blk_cgroup_bio_start+0x9c/0x174 block/blk-cgroup.c:1913 submit_bio_checks+0x200/0xad0 block/blk-core.c:893 submit_bio_noacct+0x28/0x3fc block/blk-core.c:1032 submit_bio+0x58/0x21c block/blk-core.c:1118 submit_bh_wbc+0x188/0x1b8 fs/buffer.c:3055 submit_bh fs/buffer.c:3061 [inline] block_read_full_page+0x520/0x624 fs/buffer.c:2340 blkdev_readpage+0x1c/0x20 fs/block_dev.c:640 do_read_cache_page+0x258/0x52c mm/filemap.c:3263 read_cache_page+0x1c/0x24 mm/filemap.c:3362 read_mapping_page include/linux/pagemap.h:500 [inline] read_part_sector+0x100/0x23c block/partitions/core.c:673 read_lba+0xb4/0x174 block/partitions/efi.c:250 find_valid_gpt block/partitions/efi.c:603 [inline] efi_partition+0x154/0xb5c block/partitions/efi.c:710 check_partition block/partitions/core.c:148 [inline] blk_add_partitions+0x148/0x82c block/partitions/core.c:610 bdev_disk_changed+0x13c/0x224 fs/block_dev.c:1268 __blkdev_get+0x2b0/0x334 fs/block_dev.c:1315 blkdev_get_by_dev fs/block_dev.c:1454 [inline] blkdev_get_by_dev+0x128/0x238 fs/block_dev.c:1422 disk_scan_partitions block/genhd.c:493 [inline] register_disk block/genhd.c:540 [inline] __device_add_disk+0x4e8/0x698 block/genhd.c:621 device_add_disk+0x14/0x18 block/genhd.c:639 add_disk include/linux/genhd.h:231 [inline] brd_init+0x148/0x1e0 drivers/block/brd.c:514 do_one_initcall+0x8c/0x59c init/main.c:1226 do_initcall_level init/main.c:1299 [inline] do_initcalls init/main.c:1315 [inline] do_basic_setup init/main.c:1335 [inline] kernel_init_freeable+0x2cc/0x330 init/main.c:1537 kernel_init+0x10/0x120 init/main.c:1424 ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158 0x0 SOFTIRQ-ON-W at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline] do_write_seqcount_begin include/linux/seqlock.h:545 [inline] u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline] blk_cgroup_bio_start+0x9c/0x174 block/blk-cgroup.c:1913 submit_bio_checks+0x200/0xad0 block/blk-core.c:893 submit_bio_noacct+0x28/0x3fc block/blk-core.c:1032 submit_bio+0x58/0x21c block/blk-core.c:1118 submit_bh_wbc+0x188/0x1b8 fs/buffer.c:3055 submit_bh fs/buffer.c:3061 [inline] block_read_full_page+0x520/0x624 fs/buffer.c:2340 blkdev_readpage+0x1c/0x20 fs/block_dev.c:640 do_read_cache_page+0x258/0x52c mm/filemap.c:3263 read_cache_page+0x1c/0x24 mm/filemap.c:3362 read_mapping_page include/linux/pagemap.h:500 [inline] read_part_sector+0x100/0x23c block/partitions/core.c:673 read_lba+0xb4/0x174 block/partitions/efi.c:250 find_valid_gpt block/partitions/efi.c:603 [inline] efi_partition+0x154/0xb5c block/partitions/efi.c:710 check_partition block/partitions/core.c:148 [inline] blk_add_partitions+0x148/0x82c block/partitions/core.c:610 bdev_disk_changed+0x13c/0x224 fs/block_dev.c:1268 __blkdev_get+0x2b0/0x334 fs/block_dev.c:1315 blkdev_get_by_dev fs/block_dev.c:1454 [inline] blkdev_get_by_dev+0x128/0x238 fs/block_dev.c:1422 disk_scan_partitions block/genhd.c:493 [inline] register_disk block/genhd.c:540 [inline] __device_add_disk+0x4e8/0x698 block/genhd.c:621 device_add_disk+0x14/0x18 block/genhd.c:639 add_disk include/linux/genhd.h:231 [inline] brd_init+0x148/0x1e0 drivers/block/brd.c:514 do_one_initcall+0x8c/0x59c init/main.c:1226 do_initcall_level init/main.c:1299 [inline] do_initcalls init/main.c:1315 [inline] do_basic_setup init/main.c:1335 [inline] kernel_init_freeable+0x2cc/0x330 init/main.c:1537 kernel_init+0x10/0x120 init/main.c:1424 ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158 0x0 INITIAL USE at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 do_write_seqcount_begin_nested include/linux/seqlock.h:520 [inline] do_write_seqcount_begin include/linux/seqlock.h:545 [inline] u64_stats_update_begin include/linux/u64_stats_sync.h:129 [inline] blk_cgroup_bio_start+0x9c/0x174 block/blk-cgroup.c:1913 submit_bio_checks+0x200/0xad0 block/blk-core.c:893 submit_bio_noacct+0x28/0x3fc block/blk-core.c:1032 submit_bio+0x58/0x21c block/blk-core.c:1118 submit_bh_wbc+0x188/0x1b8 fs/buffer.c:3055 submit_bh fs/buffer.c:3061 [inline] block_read_full_page+0x520/0x624 fs/buffer.c:2340 blkdev_readpage+0x1c/0x20 fs/block_dev.c:640 do_read_cache_page+0x258/0x52c mm/filemap.c:3263 read_cache_page+0x1c/0x24 mm/filemap.c:3362 read_mapping_page include/linux/pagemap.h:500 [inline] read_part_sector+0x100/0x23c block/partitions/core.c:673 read_lba+0xb4/0x174 block/partitions/efi.c:250 find_valid_gpt block/partitions/efi.c:603 [inline] efi_partition+0x154/0xb5c block/partitions/efi.c:710 check_partition block/partitions/core.c:148 [inline] blk_add_partitions+0x148/0x82c block/partitions/core.c:610 bdev_disk_changed+0x13c/0x224 fs/block_dev.c:1268 __blkdev_get+0x2b0/0x334 fs/block_dev.c:1315 blkdev_get_by_dev fs/block_dev.c:1454 [inline] blkdev_get_by_dev+0x128/0x238 fs/block_dev.c:1422 disk_scan_partitions block/genhd.c:493 [inline] register_disk block/genhd.c:540 [inline] __device_add_disk+0x4e8/0x698 block/genhd.c:621 device_add_disk+0x14/0x18 block/genhd.c:639 add_disk include/linux/genhd.h:231 [inline] brd_init+0x148/0x1e0 drivers/block/brd.c:514 do_one_initcall+0x8c/0x59c init/main.c:1226 do_initcall_level init/main.c:1299 [inline] do_initcalls init/main.c:1315 [inline] do_basic_setup init/main.c:1335 [inline] kernel_init_freeable+0x2cc/0x330 init/main.c:1537 kernel_init+0x10/0x120 init/main.c:1424 ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158 0x0 INITIAL READ USE at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] __u64_stats_fetch_begin include/linux/u64_stats_sync.h:165 [inline] u64_stats_fetch_begin include/linux/u64_stats_sync.h:176 [inline] blkcg_rstat_flush+0xfc/0x61c block/blk-cgroup.c:777 cgroup_rstat_flush_locked+0x424/0x624 kernel/cgroup/rstat.c:162 cgroup_rstat_flush_hold kernel/cgroup/rstat.c:229 [inline] cgroup_base_stat_cputime_show+0x68/0x1c4 kernel/cgroup/rstat.c:436 cpu_stat_show+0x48/0x4b4 kernel/cgroup/cgroup.c:3532 cgroup_seqfile_show+0x50/0xc4 kernel/cgroup/cgroup.c:3759 kernfs_seq_show+0x2c/0x30 fs/kernfs/file.c:168 seq_read_iter+0x1c4/0x5a8 fs/seq_file.c:227 kernfs_fop_read_iter+0x138/0x1a8 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:1971 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x214/0x33c fs/read_write.c:496 ksys_read+0x68/0xec fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] sys_read+0x10/0x14 fs/read_write.c:642 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x76ff0038 } ... key at: [<832fe198>] __key.3+0x0/0x8 ... acquired at: lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510 lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] __u64_stats_fetch_begin include/linux/u64_stats_sync.h:165 [inline] u64_stats_fetch_begin include/linux/u64_stats_sync.h:176 [inline] blkcg_rstat_flush+0xfc/0x61c block/blk-cgroup.c:777 cgroup_rstat_flush_locked+0x424/0x624 kernel/cgroup/rstat.c:162 cgroup_rstat_flush_hold kernel/cgroup/rstat.c:229 [inline] cgroup_base_stat_cputime_show+0x68/0x1c4 kernel/cgroup/rstat.c:436 cpu_stat_show+0x48/0x4b4 kernel/cgroup/cgroup.c:3532 cgroup_seqfile_show+0x50/0xc4 kernel/cgroup/cgroup.c:3759 kernfs_seq_show+0x2c/0x30 fs/kernfs/file.c:168 seq_read_iter+0x1c4/0x5a8 fs/seq_file.c:227 kernfs_fop_read_iter+0x138/0x1a8 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:1971 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x214/0x33c fs/read_write.c:496 ksys_read+0x68/0xec fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] sys_read+0x10/0x14 fs/read_write.c:642 ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64 0x76ff0038 stack backtrace: CPU: 1 PID: 4395 Comm: syz-executor.0 Not tainted 5.12.0-rc3-syzkaller #0 Hardware name: ARM-Versatile Express Backtrace: [<81802550>] (dump_backtrace) from [<818027c4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252) r7:00000080 r6:60000093 r5:00000000 r4:82b58344 [<818027ac>] (show_stack) from [<81809e98>] (__dump_stack lib/dump_stack.c:79 [inline]) [<818027ac>] (show_stack) from [<81809e98>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120) [<81809de0>] (dump_stack) from [<802ba4a8>] (print_bad_irq_dependency+0x3e0/0x434 kernel/locking/lockdep.c:2460) r7:86a11b38 r6:86a11b1c r5:86d26180 r4:830ee2f8 [<802ba0c8>] (print_bad_irq_dependency) from [<802bd780>] (check_irq_usage kernel/locking/lockdep.c:2689 [inline]) [<802ba0c8>] (print_bad_irq_dependency) from [<802bd780>] (check_prev_add kernel/locking/lockdep.c:2940 [inline]) [<802ba0c8>] (print_bad_irq_dependency) from [<802bd780>] (check_prevs_add kernel/locking/lockdep.c:3059 [inline]) [<802ba0c8>] (print_bad_irq_dependency) from [<802bd780>] (validate_chain kernel/locking/lockdep.c:3674 [inline]) [<802ba0c8>] (print_bad_irq_dependency) from [<802bd780>] (__lock_acquire+0x1af8/0x3318 kernel/locking/lockdep.c:4900) r10:86d26908 r9:86d26180 r8:81f47d20 r7:83278fe8 r6:81f4cd38 r5:86d268a8 r4:86d268a8 [<802bbc88>] (__lock_acquire) from [<802bfb90>] (lock_acquire.part.0+0xf0/0x41c kernel/locking/lockdep.c:5510) r10:00000080 r9:60000093 r8:00000000 r7:00000000 r6:828a2680 r5:828a2680 r4:86a11b88 [<802bfaa0>] (lock_acquire.part.0) from [<802bff28>] (lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5483) r10:803432fc r9:00000000 r8:00000001 r7:00000002 r6:00000000 r5:00000000 r4:ff78b3ec [<802bfebc>] (lock_acquire) from [<807bf6f0>] (seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline]) [<802bfebc>] (lock_acquire) from [<807bf6f0>] (__u64_stats_fetch_begin include/linux/u64_stats_sync.h:165 [inline]) [<802bfebc>] (lock_acquire) from [<807bf6f0>] (u64_stats_fetch_begin include/linux/u64_stats_sync.h:176 [inline]) [<802bfebc>] (lock_acquire) from [<807bf6f0>] (blkcg_rstat_flush+0xfc/0x61c block/blk-cgroup.c:777) r10:86c26e00 r9:a0000093 r8:00000001 r7:ff78b3ec r6:ff78b400 r5:ff78b418 r4:ff78b3e8 [<807bf5f4>] (blkcg_rstat_flush) from [<803432fc>] (cgroup_rstat_flush_locked+0x424/0x624 kernel/cgroup/rstat.c:162) r10:86b24000 r9:82a22928 r8:00000000 r7:82b0e4c8 r6:86bd8c00 r5:86b241d4 r4:86b24000 [<80342ed8>] (cgroup_rstat_flush_locked) from [<80343a18>] (cgroup_rstat_flush_hold kernel/cgroup/rstat.c:229 [inline]) [<80342ed8>] (cgroup_rstat_flush_locked) from [<80343a18>] (cgroup_base_stat_cputime_show+0x68/0x1c4 kernel/cgroup/rstat.c:436) r10:00000001 r9:00400cc0 r8:857cd110 r7:857cd128 r6:85964640 r5:857cd110 r4:86b24000 [<803439b0>] (cgroup_base_stat_cputime_show) from [<80337e68>] (cpu_stat_show+0x48/0x4b4 kernel/cgroup/cgroup.c:3532) r9:00400cc0 r8:86a11f08 r7:857cd128 r6:85964640 r5:857cd110 r4:86b24000 [<80337e20>] (cpu_stat_show) from [<80336224>] (cgroup_seqfile_show+0x50/0xc4 kernel/cgroup/cgroup.c:3759) r8:86a11f08 r7:857cd128 r6:85964640 r5:857cd110 r4:80337e20 [<803361d4>] (cgroup_seqfile_show) from [<805ba62c>] (kernfs_seq_show+0x2c/0x30 fs/kernfs/file.c:168) r7:857cd128 r6:85964640 r5:00000000 r4:857cd110 [<805ba600>] (kernfs_seq_show) from [<8050f06c>] (seq_read_iter+0x1c4/0x5a8 fs/seq_file.c:227) [<8050eea8>] (seq_read_iter) from [<805bab68>] (kernfs_fop_read_iter+0x138/0x1a8 fs/kernfs/file.c:241) r10:00000000 r9:86a11f68 r8:00000000 r7:86a11ef0 r6:85964640 r5:86a11f08 r4:86bb1a00 [<805baa30>] (kernfs_fop_read_iter) from [<804da704>] (call_read_iter include/linux/fs.h:1971 [inline]) [<805baa30>] (kernfs_fop_read_iter) from [<804da704>] (new_sync_read fs/read_write.c:415 [inline]) [<805baa30>] (kernfs_fop_read_iter) from [<804da704>] (vfs_read+0x214/0x33c fs/read_write.c:496) r10:00000000 r9:86a11f68 r8:00000000 r7:00000000 r6:85964640 r5:00000000 r4:00000051 [<804da4f0>] (vfs_read) from [<804dabe4>] (ksys_read+0x68/0xec fs/read_write.c:634) r10:00000003 r9:86a10000 r8:80200224 r7:00000000 r6:00000000 r5:85964640 r4:85964643 [<804dab7c>] (ksys_read) from [<804dac78>] (__do_sys_read fs/read_write.c:644 [inline]) [<804dab7c>] (ksys_read) from [<804dac78>] (sys_read+0x10/0x14 fs/read_write.c:642) r7:00000003 r6:ffffffff r5:00000000 r4:00000000 [<804dac68>] (sys_read) from [<80200060>] (ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64) Exception stack(0x86a11fa8 to 0x86a11ff0) 1fa0: 00000000 00000000 00000004 200000c0 00000051 00000000 1fc0: 00000000 00000000 ffffffff 00000003 7e93d32a 76ff06d0 7e93d4b4 76ff020c 1fe0: 76ff0048 76ff0038 00018d54 0004b8b0 --- 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 syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
