rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17176/1:b..l rcu: (detected by 1, t=10504 jiffies, g=100289, q=306 ncpus=2) task:syz.0.3996 state:R running task stack:26728 pid:17176 tgid:17175 ppid:16307 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_is_held_type+0x137/0x190 kernel/locking/lockdep.c:5948 Code: 01 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 a9 52 38 07 <48> 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0000:ffffc900035075d8 EFLAGS: 00000206 RAX: f19ef4416636b900 RBX: 0000000000000000 RCX: f19ef4416636b900 RDX: ffff88801e37bc00 RSI: ffffffff8db6a54c RDI: ffffffff8be29000 RBP: 00000000ffffffff R08: 0000000000000000 R09: ffffffff84a9c77d R10: dffffc0000000000 R11: fffff940003f531f R12: 0000000000000246 R13: ffff88801e37bc00 R14: ffffffff8e13f200 R15: 0000000000000003 lock_is_held include/linux/lockdep.h:249 [inline] rcu_read_lock_sched_held+0x89/0x100 kernel/rcu/update.c:126 task_css include/linux/cgroup.h:446 [inline] blkcg_css+0x71/0x1d0 block/blk-cgroup.c:110 blk_cgroup_congested+0xbc/0x210 block/blk-cgroup.c:2256 __folio_throttle_swaprate+0x80/0x1c0 mm/swapfile.c:3913 folio_throttle_swaprate include/linux/swap.h:636 [inline] shmem_add_to_page_cache+0x72c/0xb10 mm/shmem.c:898 shmem_alloc_and_add_folio+0x846/0xf60 mm/shmem.c:1916 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532 shmem_get_folio mm/shmem.c:2638 [inline] shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3288 generic_perform_write+0x2c4/0x910 mm/filemap.c:4103 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3463 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x548/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9a50b8d41f RSP: 002b:00007f9a51a28df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f9a50b8d41f RDX: 0000000001000000 RSI: 00007f9a46400000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009687 R10: 000020000001c302 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f9a51a28ef0 R14: 00007f9a51a28eb0 R15: 00007f9a46400000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g100289 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=42214 rcu: rcu_preempt kthread starved for 10502 jiffies! g100289 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17186 Comm: syz.1.3995 Not tainted 6.15.0-rc7-next-20250522-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:match_held_lock+0x7b/0xc0 kernel/locking/lockdep.c:5340 Code: c7 c2 30 33 45 93 48 29 d0 48 c1 f8 03 48 ba 29 5c 8f c2 f5 28 5c 8f 48 0f af d0 bb 01 00 00 00 48 39 ca 74 02 31 db 89 d8 5b <41> 5e e9 fe c9 02 00 cc 90 e8 a7 ba 58 f9 85 c0 74 22 83 3d 40 36 RSP: 0018:ffffc90000007c18 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff88802c042968 RCX: 1889bbc24da47600 RDX: ffff88802c041e00 RSI: ffff8880251fb300 RDI: ffff88802c042968 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f7c R12: 0000000000000046 R13: ffff88802c041e00 R14: ffff8880251fb300 R15: 0000000000000003 FS: 00007f2961b996c0(0000) GS:ffff888125c59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3fc708 CR3: 0000000077678000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5604 [inline] lock_is_held_type+0xa8/0x190 kernel/locking/lockdep.c:5943 lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0xe7/0xc90 net/sched/sch_taprio.c:925 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x90 kernel/kcov.c:313 Code: 7c 11 10 48 89 74 11 18 48 89 44 11 20 e9 18 a5 a6 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 14 25 08 70 9c 92 65 8b 0d 38 2b RSP: 0018:ffffc90004e162b0 EFLAGS: 00000283 RAX: ffffffff84c79c20 RBX: 000000000000000c RCX: 0000000000000002 RDX: ffff88802c041e00 RSI: 000000000000000c RDI: 0000000000000040 RBP: 0000000000000005 R08: ffff88801123a4dc R09: ffff88801123a4db R10: 1ffff1100224749b R11: ffffed1006ab1b50 R12: dffffc0000000000 R13: 0000000000000007 R14: ffff888035580028 R15: 0000000000000005 add_bits+0xea/0x9d0 lib/842/842_compress.c:181 add_template lib/842/842_compress.c:233 [inline] process_next lib/842/842_compress.c:460 [inline] sw842_compress+0x1b4b/0x49d0 lib/842/842_compress.c:545 scomp_acomp_comp_decomp+0x6dd/0x9e0 crypto/scompress.c:-1 crypto_acomp_compress+0x42f/0xb20 crypto/acompress.c:291 zswap_compress mm/zswap.c:977 [inline] zswap_store_page mm/zswap.c:1495 [inline] zswap_store+0xe3c/0x1d10 mm/zswap.c:1604 swap_writeout+0x6d9/0xce0 mm/page_io.c:277 pageout mm/vmscan.c:720 [inline] shrink_folio_list+0x31bd/0x4e90 mm/vmscan.c:1452 reclaim_folio_list+0xeb/0x500 mm/vmscan.c:2232 reclaim_pages+0x49a/0x5b0 mm/vmscan.c:2269 madvise_cold_or_pageout_pte_range+0x19be/0x1d40 mm/madvise.c:563 walk_pmd_range mm/pagewalk.c:130 [inline] walk_pud_range mm/pagewalk.c:226 [inline] walk_p4d_range mm/pagewalk.c:264 [inline] walk_pgd_range+0x1093/0x1e70 mm/pagewalk.c:305 __walk_page_range+0x14c/0x710 mm/pagewalk.c:412 walk_page_range_mm+0x42d/0x620 mm/pagewalk.c:505 madvise_pageout_page_range mm/madvise.c:622 [inline] madvise_pageout mm/madvise.c:649 [inline] madvise_vma_behavior mm/madvise.c:1278 [inline] madvise_walk_vmas mm/madvise.c:1539 [inline] madvise_do_behavior+0x1d2f/0x3750 mm/madvise.c:1731 do_madvise+0x174/0x220 mm/madvise.c:1824 __do_sys_madvise mm/madvise.c:1833 [inline] __se_sys_madvise mm/madvise.c:1831 [inline] __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:1831 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2960d8e969 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:00007f2961b99038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f2960fb6160 RCX: 00007f2960d8e969 RDX: 0000000000000015 RSI: 000000000040001e RDI: 0000200000000000 RBP: 00007f2960e10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f2960fb6160 R15: 00007ffe388df438