Hi Kent et al, On 6.6.0-rc7-next-20231024 with my bcachefs exerciser [1], I was able to reproduce three related kernel warnings due to RCU grace period counts being zero, ie WARN_ON_ONCE(READ_ONCE(rsp->gp_count) == 0). If this is something of interest, I'll find a minimal reproducer. These warnings aside, bcachefs is looking really solid. Thanks, Daniel -- [1] https://github.com/dblueman/bcachefs-gym -- [2] WARNING: CPU: 15 PID: 259240 at kernel/rcu/sync.c:171 rcu_sync_exit+0xe3/0xf0 Modules linked in: brd tls cfg80211 intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd kvm_amd binfmt_misc kvm irqbypass ipmi_ssif rapl wmi_bmof nls_iso8859_1 ccp ptdma k10temp acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler input_leds joydev mac_hid efi_pstore dmi_sysfs ip_tables x_tables autofs4 rndis_host cdc_ether usbnet m ii btrfs blake2b_generic hid_generic usbhid raid10 hid raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ast polyval_clmulni polyval_generic i2c_algo_bit ghash_clmulni_intel drm_shmem_helper sha512_ssse3 drm_kms_helper sha256_ssse3 sha1_ssse3 nvme ahci drm nvme_core tg3 l ibahci xhci_pci i2c_piix4 xhci_pci_renesas wmi aesni_intel crypto_simd cryptd [last unloaded: brd] CPU: 15 PID: 259240 Comm: bch-data/3edb8b Tainted: G W 6.6.0-rc7-next-20231024 #1 Hardware name: Supermicro AS -3014TS-i/H12SSL-i, BIOS 2.5 09/08/2022 RIP: 0010:rcu_sync_exit+0xe3/0xf0 Code: c6 e0 06 c7 b2 e8 dd 0e 01 00 4c 89 e7 e8 b5 54 91 01 5b 41 5c 41 5d 5d 31 c0 31 f6 31 ff e9 8f 35 a9 01 0f 0b e9 3d ff ff ff <0f> 0b e9 4d ff ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90024127b60 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8883b7383740 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90024127b78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8883b7383798 R13: ffff8883b7383744 R14: ffff8883b7383740 R15: ffff8883b7380498 FS: 0000000000000000(0000) GS:ffff88bf0e780000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fea708bae00 CR3: 000000034b860003 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> ? show_regs+0x6c/0x80 ? __warn+0xa4/0x1c0 ? rcu_sync_exit+0xe3/0xf0 ? report_bug+0x1bc/0x1f0 ? handle_bug+0x46/0x90 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? rcu_sync_exit+0xe3/0xf0 percpu_up_write+0x4d/0x60 bch2_replicas_gc_end+0x60/0x110 bch2_journal_flush_device_pins+0x2d7/0x4b0 ? __entry_text_end+0x102619/0x10261d ? __pfx_bch2_journal_flush_device_pins+0x10/0x10 ? __pfx_scnprintf+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? raw_spin_rq_unlock+0x17/0x70 ? srso_alias_return_thunk+0x5/0xfbef5 ? finish_task_switch.isra.0+0xc1/0x410 ? __switch_to+0x281/0x6d0 bch2_data_job+0x1fb/0x500 ? __pfx_bch2_data_job+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? try_to_wake_up+0x4b1/0xca0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_bch2_data_thread+0x10/0x10 bch2_data_thread+0x60/0xa0 kthread+0x188/0x1d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x47/0x80 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> WARNING: CPU: 15 PID: 259240 at kernel/rcu/sync.c:129 rcu_sync_enter+0x1d6/0x200 Modules linked in: brd tls cfg80211 intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd kvm_amd binfmt_misc kvm irqbypass ipmi_ssif rapl wmi_bmof nls_iso8859_1 ccp ptdma k10temp acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler input_leds joydev mac_hid efi_pstore dmi_sysfs ip_tables x_tables autofs4 rndis_host cdc_ether usbnet m ii btrfs blake2b_generic hid_generic usbhid raid10 hid raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ast polyval_clmulni polyval_generic i2c_algo_bit ghash_clmulni_intel drm_shmem_helper sha512_ssse3 drm_kms_helper sha256_ssse3 sha1_ssse3 nvme ahci drm nvme_core tg3 l ibahci xhci_pci i2c_piix4 xhci_pci_renesas wmi aesni_intel crypto_simd cryptd [last unloaded: brd] CPU: 15 PID: 259240 Comm: bch-data/3edb8b Tainted: G W 6.6.0-rc7-next-20231024 #1 Hardware name: Supermicro AS -3014TS-i/H12SSL-i, BIOS 2.5 09/08/2022 RIP: 0010:rcu_sync_enter+0x1d6/0x200 Code: 89 ef e8 2d fb f9 ff 48 89 df e8 35 45 3f 00 8b 03 83 f8 01 7e d8 48 8d b5 68 ff ff ff 4c 89 ef e8 6f c1 f9 ff e9 0b ff ff ff <0f> 0b 4c 89 ff 41 83 c6 01 e8 ec 45 3f 00 44 89 73 04 4c 89 ef e8 RSP: 0018:ffffc90024127b00 EFLAGS: 00010086 RAX: 0000000000000000 RBX: ffff8883b7383740 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90024127bc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92004824f60 R13: ffff8883b7383748 R14: 00000000ffffffff R15: ffff8883b7383744 FS: 0000000000000000(0000) GS:ffff88bf0e780000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fea708bae00 CR3: 000000034b860003 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> ? show_regs+0x6c/0x80 ? __warn+0xa4/0x1c0 ? rcu_sync_enter+0x1d6/0x200 ? report_bug+0x1bc/0x1f0 ? handle_bug+0x46/0x90 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? rcu_sync_enter+0x1d6/0x200 ? __pfx_rcu_sync_enter+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __kasan_check_write+0x14/0x30 percpu_down_write+0x2f/0x2b0 ? bch2_replicas_gc2+0x122/0x6f0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __kmalloc+0x61/0xf0 bch2_replicas_gc2+0x155/0x6f0 ? __pfx_bch2_replicas_gc2+0x10/0x10 ? raw_spin_rq_unlock+0x17/0x70 ? finish_task_switch.isra.0+0xc1/0x410 ? __switch_to+0x281/0x6d0 bch2_data_job+0x298/0x500 ? __pfx_bch2_data_job+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? try_to_wake_up+0x4b1/0xca0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_bch2_data_thread+0x10/0x10 bch2_data_thread+0x60/0xa0 kthread+0x188/0x1d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x47/0x80 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> WARNING: CPU: 38 PID: 262351 at kernel/rcu/sync.c:193 rcu_sync_dtor+0x96/0xb0 Modules linked in: brd tls cfg80211 intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd kvm_amd binfmt_misc kvm irqbypass ipmi_ssif rapl wmi_bmof nls_iso8859_1 ccp ptdma k10temp acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler input_leds joydev mac_hid efi_pstore dmi_sysfs ip_tables x_tables autofs4 rndis_host cdc_ether usbnet mii btrfs blake2b_generic hid_generic usbhid raid10 hid raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ast polyval_clmulni polyval_generic i2c_algo_bit ghash_clmulni_intel drm_shmem_helper sha512_ssse3 drm_kms_helper sha256_ssse3 sha1_ssse3 nvme ahci drm nvme_core tg3 libahci xhci_pci i2c_piix4 xhci_pci_renesas wmi aesni_intel crypto_simd cryptd [last unloaded: brd] CPU: 38 PID: 262351 Comm: umount Tainted: G W 6.6.0-rc7-next-20231024 #1 Hardware name: Supermicro AS -3014TS-i/H12SSL-i, BIOS 2.5 09/08/2022 RIP: 0010:rcu_sync_dtor+0x96/0xb0 Code: e8 4f 44 3f 00 c7 03 03 00 00 00 4c 89 e7 e8 01 54 91 01 e8 fc 80 00 00 48 89 df e8 54 43 3f 00 8b 03 85 c0 74 c8 0f 0b eb c4 <0f> 0b 48 89 df e8 40 43 3f 00 8b 03 83 f8 02 75 89 0f 0b eb 85 cc RSP: 0018:ffffc9000d35fc60 EFLAGS: 00010286 RAX: 00000000ffffffff RBX: ffff8883b7383740 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000d35fc78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8883b7383770 R13: ffff8883b7380040 R14: ffff8883b7380000 R15: 0000000000000000 FS: 00007f2033aef800(0000) GS:ffff88bf0f300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fea708bae00 CR3: 000000042bf7e005 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> ? show_regs+0x6c/0x80 ? __warn+0xa4/0x1c0 ? rcu_sync_dtor+0x96/0xb0 ? report_bug+0x1bc/0x1f0 ? handle_bug+0x46/0x90 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? rcu_sync_dtor+0x96/0xb0 percpu_free_rwsem+0x2a/0x60 bch2_fs_release+0x131/0x340 kobject_put+0x103/0x250 bch2_fs_free+0x144/0x190 bch2_kill_sb+0x50/0x70 deactivate_locked_super+0x69/0x110 deactivate_super+0x64/0x80 cleanup_mnt+0x141/0x220 __cleanup_mnt+0x12/0x20 task_work_run+0x10b/0x190 ? __pfx_task_work_run+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __x64_sys_umount+0xff/0x110 exit_to_user_mode_prepare+0x169/0x190 syscall_exit_to_user_mode+0x28/0x60 do_syscall_64+0x6b/0xf0 ? srso_alias_return_thunk+0x5/0xfbef5 ? syscall_exit_to_user_mode+0x36/0x60 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_syscall_64+0x6b/0xf0 ? srso_alias_return_thunk+0x5/0xfbef5 ? irqentry_exit_to_user_mode+0x17/0x20 ? srso_alias_return_thunk+0x5/0xfbef5 ? irqentry_exit+0x43/0x50 ? srso_alias_return_thunk+0x5/0xfbef5 ? sysvec_call_function+0x48/0xd0 entry_SYSCALL_64_after_hwframe+0x6c/0x74 RIP: 0033:0x7f203391ee5b Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 89 6f 0d 00 f7 d8 RSP: 002b:00007ffcadb990e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000560145c5a5c0 RCX: 00007f203391ee5b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000560145c5e820 RBP: 0000560145c5a6d8 R08: 0000000000000073 R09: 00007ffcadb98031 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000560145c5e820 R14: 0000560145c5e7f0 R15: 0000560145c5a5c0 </TASK> -- Daniel J Blueman
