rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8/1:b..l P25311/1:b..l P25346/1:b..l (detected by 1, t=10502 jiffies, g=213089, q=17) task:syz-executor.4 state:R running task stack:29168 pid:25346 ppid: 6540 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x33/0x510 kernel/locking/lockdep.c:5593 Code: df 41 57 41 89 f7 41 56 49 89 fe 41 55 41 89 d5 41 54 41 89 cc 55 44 89 c5 53 48 81 ec b0 00 00 00 48 8d 5c 24 10 4c 89 0c 24 <48> c7 44 24 10 b3 8a b5 41 48 c1 eb 03 48 c7 44 24 18 ca eb 14 8b RSP: 0018:ffffc900068af978 EFLAGS: 00000286 RAX: dffffc0000000000 RBX: ffffc900068af988 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8b97fe20 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8209bc0c R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8b97fe20 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:687 [inline] ext4_get_group_desc+0x146/0x500 fs/ext4/balloc.c:284 recently_deleted fs/ext4/ialloc.c:685 [inline] find_inode_bit+0x1c4/0x580 fs/ext4/ialloc.c:731 __ext4_new_inode+0xc64/0x5ba0 fs/ext4/ialloc.c:1066 ext4_symlink+0x489/0xd50 fs/ext4/namei.c:3293 vfs_symlink fs/namei.c:4250 [inline] vfs_symlink+0x479/0x730 fs/namei.c:4235 do_symlinkat+0x261/0x2e0 fs/namei.c:4279 __do_sys_symlink fs/namei.c:4301 [inline] __se_sys_symlink fs/namei.c:4299 [inline] __x64_sys_symlink+0x75/0x90 fs/namei.c:4299 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efcfbefe1e7 RSP: 002b:00007ffc1178d098 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007efcfbefe1e7 RDX: 00007ffc1178d177 RSI: 00007efcfbf58d55 RDI: 00007ffc1178d160 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffc1178cf30 R10: 00007ffc1178cde7 R11: 0000000000000202 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffc1178d160 task:syz-executor.0 state:R running task stack:25432 pid:25311 ppid: 6532 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:197 Code: ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 79 f1 8b 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc90006c674c0 EFLAGS: 00000202 RAX: 0000000080000000 RBX: ffffc90006c67570 RCX: 0000000080000000 RDX: 0000000000000000 RSI: ffffffff83f791f5 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: ffff8880b9d32a0b R10: ffffffff83f7934b R11: 0000000000000000 R12: ffff888087bd9082 R13: ffffc90006c67588 R14: 0000000000000040 R15: 00000000000000a9 xa_is_internal include/linux/xarray.h:169 [inline] xa_is_node include/linux/xarray.h:1226 [inline] xas_start+0xd5/0x730 lib/xarray.c:189 xas_load+0x28/0x140 lib/xarray.c:233 xa_load+0xee/0x280 lib/xarray.c:1456 page_cache_ra_unbounded+0x333/0x950 mm/readahead.c:200 do_page_cache_ra mm/readahead.c:269 [inline] ondemand_readahead+0x61e/0x11d0 mm/readahead.c:552 page_cache_async_ra mm/readahead.c:609 [inline] page_cache_async_ra+0x2e1/0x3f0 mm/readahead.c:584 page_cache_async_readahead include/linux/pagemap.h:906 [inline] filemap_readahead mm/filemap.c:2520 [inline] filemap_get_pages+0x648/0x1870 mm/filemap.c:2561 filemap_read+0x2ca/0xe50 mm/filemap.c:2628 generic_file_read_iter+0x397/0x4f0 mm/filemap.c:2779 ext4_file_read_iter+0x1d4/0x5d0 fs/ext4/file.c:130 call_read_iter include/linux/fs.h:2157 [inline] do_iter_readv_writev+0x56d/0x750 fs/read_write.c:727 do_iter_read+0x2f8/0x760 fs/read_write.c:790 vfs_readv+0xe5/0x150 fs/read_write.c:910 do_preadv fs/read_write.c:1002 [inline] __do_sys_preadv fs/read_write.c:1052 [inline] __se_sys_preadv fs/read_write.c:1047 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1047 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f7cabbba8d9 RSP: 002b:00007f7ca9131188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f7cabcbef60 RCX: 00007f7cabbba8d9 RDX: 0000000000000008 RSI: 00000000200015c0 RDI: 0000000000000003 RBP: 00007f7cabc14cb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001300 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdf11df2df R14: 00007f7ca9131300 R15: 0000000000022000 task:kworker/u4:0 state:R running task stack:24864 pid: 8 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:rcu_read_lock include/linux/rcupdate.h:688 [inline] RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline] RIP: 0010:batadv_nc_worker+0x141/0xfa0 net/batman-adv/network-coding.c:721 Code: b9 02 00 00 00 68 63 6c d2 88 48 c7 c7 20 fe 97 8b e8 c3 ea 88 f8 e8 be 47 8f f8 31 ff 89 c5 89 c6 e8 13 98 a3 f8 40 84 ed 58 <0f> 84 52 0a 00 00 e8 c4 91 a3 f8 48 89 d8 48 c1 e8 03 42 80 3c 30 RSP: 0018:ffffc90000cd7c90 EFLAGS: 00000202 RAX: ffffffff88d26c63 RBX: ffff88807cb19168 RCX: ffff888011f25580 RDX: 0000000000000000 RSI: ffff888011f25580 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff88d26cad R11: 0000000000000000 R12: ffffc90000cd7db0 R13: 0000000000000000 R14: dffffc0000000000 R15: 000000000000022d process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g213089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=108032 rcu: rcu_preempt kthread starved for 10502 jiffies! g213089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: ---------------- Code disassembly (best guess): 0: df 41 57 filds 0x57(%rcx) 3: 41 89 f7 mov %esi,%r15d 6: 41 56 push %r14 8: 49 89 fe mov %rdi,%r14 b: 41 55 push %r13 d: 41 89 d5 mov %edx,%r13d 10: 41 54 push %r12 12: 41 89 cc mov %ecx,%r12d 15: 55 push %rbp 16: 44 89 c5 mov %r8d,%ebp 19: 53 push %rbx 1a: 48 81 ec b0 00 00 00 sub $0xb0,%rsp 21: 48 8d 5c 24 10 lea 0x10(%rsp),%rbx 26: 4c 89 0c 24 mov %r9,(%rsp) * 2a: 48 c7 44 24 10 b3 8a movq $0x41b58ab3,0x10(%rsp) <-- trapping instruction 31: b5 41 33: 48 c1 eb 03 shr $0x3,%rbx 37: 48 c7 44 24 18 ca eb movq $0xffffffff8b14ebca,0x18(%rsp) 3e: 14 8b