* bcache: oops when writing to writeback_percent without a cache device @ 2019-06-04 11:00 Bjørn Forsman 2019-06-04 14:59 ` Coly Li 0 siblings, 1 reply; 6+ messages in thread From: Bjørn Forsman @ 2019-06-04 11:00 UTC (permalink / raw) To: Coly Li, Kent Overstreet, linux-bcache, LKML Hi all, I get a kernel oops from bcache when writing to /sys/block/bcache0/bcache/writeback_percent and there is no attached cache device. See the oops itself below my signature. This is on Linux 4.19.46. I looked in git and see many commits to bcache lately, but none seem to address this particular issue. Background: I'm writing to .../writeback_percent with systemd-tmpfiles. I'd rather not replace it with a script that figures out whether or not the kernel will oops if writing to the sysfs file -- the kernel should not oops in the first place. -- Best regards, Bjørn Forsman Jun 04 12:35:42 kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000340 Jun 04 12:35:42 kernel: PGD 0 P4D 0 Jun 04 12:35:42 kernel: Oops: 0000 [#1] SMP PTI Jun 04 12:35:42 kernel: CPU: 6 PID: 20266 Comm: kworker/6:220 Not tainted 4.19.46 #1-NixOS Jun 04 12:35:42 kernel: Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme4/3.1, BIOS P3.60 04/06/2018 Jun 04 12:35:42 kernel: Workqueue: events update_writeback_rate [bcache] Jun 04 12:35:42 kernel: RIP: 0010:update_writeback_rate+0x2f/0x2e0 [bcache] Jun 04 12:35:42 kernel: Code: 41 57 41 56 41 55 41 54 55 53 48 8b af 00 f4 ff ff f0 80 8f 20 f4 ff ff 10 f0 83 44 24 fc 00 48 8b 87 20 f4 ff ff a8 08 74 51 <48> 8b 85 40 03 00 00 a8 08 75 46 8b 47 e8 48 89 fb 85 c0 74 09 80 Jun 04 12:35:42 kernel: RSP: 0018:ffffafbfccdbbe68 EFLAGS: 00010202 Jun 04 12:35:42 kernel: RAX: 0000000000000018 RBX: ffff97bf75f60c80 RCX: ffff97bf7f9a0ee0 Jun 04 12:35:42 kernel: RDX: ffff97bf7f9a0ee0 RSI: 0000000000000180 RDI: ffff97bf75f60c80 Jun 04 12:35:42 kernel: RBP: 0000000000000000 R08: 000073746e657665 R09: 8080808080808080 Jun 04 12:35:42 kernel: R10: ffffafbfc3207de8 R11: fefefefefefefeff R12: ffff97bf7f9a4d00 Jun 04 12:35:42 kernel: R13: 0000000000000000 R14: ffff97bf75270180 R15: 0ffff97bf7f9a4d0 Jun 04 12:35:42 kernel: FS: 0000000000000000(0000) GS:ffff97bf7f980000(0000) knlGS:0000000000000000 Jun 04 12:35:42 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jun 04 12:35:42 kernel: CR2: 0000000000000340 CR3: 0000000709a0a004 CR4: 00000000001606e0 Jun 04 12:35:42 kernel: Call Trace: Jun 04 12:35:42 kernel: process_one_work+0x1f4/0x3e0 Jun 04 12:35:42 kernel: worker_thread+0x2d/0x3e0 Jun 04 12:35:42 kernel: ? process_one_work+0x3e0/0x3e0 Jun 04 12:35:42 kernel: kthread+0x113/0x130 Jun 04 12:35:42 kernel: ? kthread_create_worker_on_cpu+0x70/0x70 Jun 04 12:35:42 kernel: ret_from_fork+0x35/0x40 Jun 04 12:35:42 kernel: Modules linked in: tcp_diag inet_diag iptable_mangle xt_CHECKSUM ipt_MASQUERADE ipt_REJECT nf_reject_ipv4 bridge stp llc nf_tables nfnetlink devlink af_packet msr nouveau edac_core x86_pkg_temp_thermal nls_iso8859_1 video intel_powerclamp ttm nls_cp437 drm_kms_helper vfat coretemp drm fat crct10dif_pclmul agpgart iptable_nat nf_nat_ipv4 nf_nat xt_conntrack crc32_pclmul snd_hda_codec_hdmi nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ip6t_rpfilter i2c_algo_bit ghash_clmulni_intel fb_sys_fops syscopyarea ipt_rpfilter sysfillrect pcbc aesni_intel aes_x86_64 crypto_simd cryptd sysimgblt ip6table_raw iptable_raw snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel xt_pkttype glue_helper snd_hda_codec nf_log_ipv6 intel_cstate uas snd_hda_core intel_uncore deflate e1000e snd_hwdep Jun 04 12:35:42 kernel: snd_pcm iTCO_wdt joydev snd_timer mousedev mxm_wmi intel_wmi_thunderbolt nf_log_ipv4 evdev input_leds led_class snd nf_log_common xt_LOG efi_pstore intel_rapl_perf soundcore mac_hid pstore xt_tcpudp efivars ptp nvme mei_me mei pps_core i2c_i801 nvme_core i2c_core lpc_ich wmi button ip6table_filter pcc_cpufreq ip6_tables iptable_filter atkbd libps2 serio loop cpufreq_powersave tun kvm_intel kvm irqbypass efivarfs ip_tables x_tables ipv6 crc_ccitt autofs4 ext4 crc32c_generic crc16 mbcache jbd2 fscrypto usb_storage bcache hid_logitech_hidpp crc64 raid1 md_mod hid_logitech_dj hid_generic usbhid hid sd_mod xhci_pci ahci xhci_hcd libahci libata ehci_pci ehci_hcd usbcore scsi_mod crc32c_intel usb_common rtc_cmos dm_mod Jun 04 12:35:42 kernel: CR2: 0000000000000340 Jun 04 12:35:42 kernel: ---[ end trace 764634a58d34fb7c ]--- Jun 04 12:35:43 kernel: RIP: 0010:update_writeback_rate+0x2f/0x2e0 [bcache] Jun 04 12:35:43 kernel: Code: 41 57 41 56 41 55 41 54 55 53 48 8b af 00 f4 ff ff f0 80 8f 20 f4 ff ff 10 f0 83 44 24 fc 00 48 8b 87 20 f4 ff ff a8 08 74 51 <48> 8b 85 40 03 00 00 a8 08 75 46 8b 47 e8 48 89 fb 85 c0 74 09 80 Jun 04 12:35:43 kernel: RSP: 0018:ffffafbfccdbbe68 EFLAGS: 00010202 Jun 04 12:35:43 kernel: RAX: 0000000000000018 RBX: ffff97bf75f60c80 RCX: ffff97bf7f9a0ee0 Jun 04 12:35:43 kernel: RDX: ffff97bf7f9a0ee0 RSI: 0000000000000180 RDI: ffff97bf75f60c80 Jun 04 12:35:43 kernel: RBP: 0000000000000000 R08: 000073746e657665 R09: 8080808080808080 Jun 04 12:35:43 kernel: R10: ffffafbfc3207de8 R11: fefefefefefefeff R12: ffff97bf7f9a4d00 Jun 04 12:35:43 kernel: R13: 0000000000000000 R14: ffff97bf75270180 R15: 0ffff97bf7f9a4d0 Jun 04 12:35:43 kernel: FS: 0000000000000000(0000) GS:ffff97bf7f980000(0000) knlGS:0000000000000000 Jun 04 12:35:43 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jun 04 12:35:43 kernel: CR2: 0000000000000340 CR3: 0000000709a0a004 CR4: 00000000001606e0 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: bcache: oops when writing to writeback_percent without a cache device 2019-06-04 11:00 bcache: oops when writing to writeback_percent without a cache device Bjørn Forsman @ 2019-06-04 14:59 ` Coly Li 2019-06-04 15:41 ` Coly Li 0 siblings, 1 reply; 6+ messages in thread From: Coly Li @ 2019-06-04 14:59 UTC (permalink / raw) To: Bjørn Forsman; +Cc: Kent Overstreet, linux-bcache, LKML On 2019/6/4 7:00 下午, Bjørn Forsman wrote: > Hi all, > > I get a kernel oops from bcache when writing to > /sys/block/bcache0/bcache/writeback_percent and there is no attached > cache device. See the oops itself below my signature. > > This is on Linux 4.19.46. I looked in git and see many commits to > bcache lately, but none seem to address this particular issue. > > Background: I'm writing to .../writeback_percent with > systemd-tmpfiles. I'd rather not replace it with a script that figures > out whether or not the kernel will oops if writing to the sysfs file > -- the kernel should not oops in the first place. Hi Bjorn, Thank you for the reporting. I believe this is a case we missed in testings. When a bcache device is not attached, it does not make sense to update the writeback rate in period by the changing of writeback_percent. I will post a patch for your testing soon. Coly Li > > Jun 04 12:35:42 kernel: BUG: unable to handle kernel NULL pointer > dereference at 0000000000000340 > Jun 04 12:35:42 kernel: PGD 0 P4D 0 > Jun 04 12:35:42 kernel: Oops: 0000 [#1] SMP PTI > Jun 04 12:35:42 kernel: CPU: 6 PID: 20266 Comm: kworker/6:220 Not > tainted 4.19.46 #1-NixOS > Jun 04 12:35:42 kernel: Hardware name: To Be Filled By O.E.M. To Be > Filled By O.E.M./X99 Extreme4/3.1, BIOS P3.60 04/06/2018 > Jun 04 12:35:42 kernel: Workqueue: events update_writeback_rate [bcache] > Jun 04 12:35:42 kernel: RIP: 0010:update_writeback_rate+0x2f/0x2e0 [bcache] > Jun 04 12:35:42 kernel: Code: 41 57 41 56 41 55 41 54 55 53 48 8b af > 00 f4 ff ff f0 80 8f 20 f4 ff ff 10 f0 83 44 24 fc 00 48 8b 87 20 f4 > ff ff a8 08 74 51 <48> 8b 85 40 03 00 00 a8 08 75 46 8b 47 e8 48 89 fb > 85 c0 74 09 80 > Jun 04 12:35:42 kernel: RSP: 0018:ffffafbfccdbbe68 EFLAGS: 00010202 > Jun 04 12:35:42 kernel: RAX: 0000000000000018 RBX: ffff97bf75f60c80 > RCX: ffff97bf7f9a0ee0 > Jun 04 12:35:42 kernel: RDX: ffff97bf7f9a0ee0 RSI: 0000000000000180 > RDI: ffff97bf75f60c80 > Jun 04 12:35:42 kernel: RBP: 0000000000000000 R08: 000073746e657665 > R09: 8080808080808080 > Jun 04 12:35:42 kernel: R10: ffffafbfc3207de8 R11: fefefefefefefeff > R12: ffff97bf7f9a4d00 > Jun 04 12:35:42 kernel: R13: 0000000000000000 R14: ffff97bf75270180 > R15: 0ffff97bf7f9a4d0 > Jun 04 12:35:42 kernel: FS: 0000000000000000(0000) > GS:ffff97bf7f980000(0000) knlGS:0000000000000000 > Jun 04 12:35:42 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > Jun 04 12:35:42 kernel: CR2: 0000000000000340 CR3: 0000000709a0a004 > CR4: 00000000001606e0 > Jun 04 12:35:42 kernel: Call Trace: > Jun 04 12:35:42 kernel: process_one_work+0x1f4/0x3e0 > Jun 04 12:35:42 kernel: worker_thread+0x2d/0x3e0 > Jun 04 12:35:42 kernel: ? process_one_work+0x3e0/0x3e0 > Jun 04 12:35:42 kernel: kthread+0x113/0x130 > Jun 04 12:35:42 kernel: ? kthread_create_worker_on_cpu+0x70/0x70 > Jun 04 12:35:42 kernel: ret_from_fork+0x35/0x40 > Jun 04 12:35:42 kernel: Modules linked in: tcp_diag inet_diag > iptable_mangle xt_CHECKSUM ipt_MASQUERADE ipt_REJECT nf_reject_ipv4 > bridge stp llc nf_tables nfnetlink devlink af_packet msr nouveau > edac_core x86_pkg_temp_thermal nls_iso8859_1 video intel_powerclamp > ttm nls_cp437 drm_kms_helper vfat coretemp drm fat crct10dif_pclmul > agpgart iptable_nat nf_nat_ipv4 nf_nat xt_conntrack crc32_pclmul > snd_hda_codec_hdmi nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 > libcrc32c ip6t_rpfilter i2c_algo_bit ghash_clmulni_intel fb_sys_fops > syscopyarea ipt_rpfilter sysfillrect pcbc aesni_intel aes_x86_64 > crypto_simd cryptd sysimgblt ip6table_raw iptable_raw > snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel xt_pkttype > glue_helper snd_hda_codec nf_log_ipv6 intel_cstate uas snd_hda_core > intel_uncore deflate e1000e snd_hwdep > Jun 04 12:35:42 kernel: snd_pcm iTCO_wdt joydev snd_timer mousedev > mxm_wmi intel_wmi_thunderbolt nf_log_ipv4 evdev input_leds led_class > snd nf_log_common xt_LOG efi_pstore intel_rapl_perf soundcore mac_hid > pstore xt_tcpudp efivars ptp nvme mei_me mei pps_core i2c_i801 > nvme_core i2c_core lpc_ich wmi button ip6table_filter pcc_cpufreq > ip6_tables iptable_filter atkbd libps2 serio loop cpufreq_powersave > tun kvm_intel kvm irqbypass efivarfs ip_tables x_tables ipv6 crc_ccitt > autofs4 ext4 crc32c_generic crc16 mbcache jbd2 fscrypto usb_storage > bcache hid_logitech_hidpp crc64 raid1 md_mod hid_logitech_dj > hid_generic usbhid hid sd_mod xhci_pci ahci xhci_hcd libahci libata > ehci_pci ehci_hcd usbcore scsi_mod crc32c_intel usb_common rtc_cmos > dm_mod > Jun 04 12:35:42 kernel: CR2: 0000000000000340 > Jun 04 12:35:42 kernel: ---[ end trace 764634a58d34fb7c ]--- > Jun 04 12:35:43 kernel: RIP: 0010:update_writeback_rate+0x2f/0x2e0 [bcache] > Jun 04 12:35:43 kernel: Code: 41 57 41 56 41 55 41 54 55 53 48 8b af > 00 f4 ff ff f0 80 8f 20 f4 ff ff 10 f0 83 44 24 fc 00 48 8b 87 20 f4 > ff ff a8 08 74 51 <48> 8b 85 40 03 00 00 a8 08 75 46 8b 47 e8 48 89 fb > 85 c0 74 09 80 > Jun 04 12:35:43 kernel: RSP: 0018:ffffafbfccdbbe68 EFLAGS: 00010202 > Jun 04 12:35:43 kernel: RAX: 0000000000000018 RBX: ffff97bf75f60c80 > RCX: ffff97bf7f9a0ee0 > Jun 04 12:35:43 kernel: RDX: ffff97bf7f9a0ee0 RSI: 0000000000000180 > RDI: ffff97bf75f60c80 > Jun 04 12:35:43 kernel: RBP: 0000000000000000 R08: 000073746e657665 > R09: 8080808080808080 > Jun 04 12:35:43 kernel: R10: ffffafbfc3207de8 R11: fefefefefefefeff > R12: ffff97bf7f9a4d00 > Jun 04 12:35:43 kernel: R13: 0000000000000000 R14: ffff97bf75270180 > R15: 0ffff97bf7f9a4d0 > Jun 04 12:35:43 kernel: FS: 0000000000000000(0000) > GS:ffff97bf7f980000(0000) knlGS:0000000000000000 > Jun 04 12:35:43 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > Jun 04 12:35:43 kernel: CR2: 0000000000000340 CR3: 0000000709a0a004 > CR4: 00000000001606e0 > -- Coly Li ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: bcache: oops when writing to writeback_percent without a cache device 2019-06-04 14:59 ` Coly Li @ 2019-06-04 15:41 ` Coly Li 2019-06-04 17:24 ` Bjørn Forsman 0 siblings, 1 reply; 6+ messages in thread From: Coly Li @ 2019-06-04 15:41 UTC (permalink / raw) To: Bjørn Forsman; +Cc: Kent Overstreet, linux-bcache, LKML [-- Attachment #1: Type: text/plain, Size: 1651 bytes --] On 2019/6/4 10:59 下午, Coly Li wrote: > On 2019/6/4 7:00 下午, Bjørn Forsman wrote: >> Hi all, >> >> I get a kernel oops from bcache when writing to >> /sys/block/bcache0/bcache/writeback_percent and there is no attached >> cache device. See the oops itself below my signature. >> >> This is on Linux 4.19.46. I looked in git and see many commits to >> bcache lately, but none seem to address this particular issue. >> >> Background: I'm writing to .../writeback_percent with >> systemd-tmpfiles. I'd rather not replace it with a script that figures >> out whether or not the kernel will oops if writing to the sysfs file >> -- the kernel should not oops in the first place. > > Hi Bjorn, > > Thank you for the reporting. I believe this is a case we missed in > testings. When a bcache device is not attached, it does not make sense > to update the writeback rate in period by the changing of writeback_percent. > > I will post a patch for your testing soon. Hi Bjorn, Could you please to try this patch ? Hope it may help a bit. Thanks. Coly Li >> >> Jun 04 12:35:42 kernel: BUG: unable to handle kernel NULL pointer >> dereference at 0000000000000340 >> Jun 04 12:35:42 kernel: PGD 0 P4D 0 >> Jun 04 12:35:42 kernel: Oops: 0000 [#1] SMP PTI >> Jun 04 12:35:42 kernel: CPU: 6 PID: 20266 Comm: kworker/6:220 Not >> tainted 4.19.46 #1-NixOS >> Jun 04 12:35:42 kernel: Hardware name: To Be Filled By O.E.M. To Be >> Filled By O.E.M./X99 Extreme4/3.1, BIOS P3.60 04/06/2018 >> Jun 04 12:35:42 kernel: Workqueue: events update_writeback_rate [bcache] >> Jun 04 12:35:42 kernel: RIP: 0010:update_writeback_rate+0x2f/0x2e0 [bcache] [snipped] [-- Attachment #2: 0001-bcache-only-set-BCACHE_DEV_WB_RUNNING-when-cached-de.patch --] [-- Type: text/plain, Size: 1830 bytes --] From 9dea1e6ad0e6c40e3bc6ee6cf4ad243c07ca6ca9 Mon Sep 17 00:00:00 2001 From: Coly Li <colyli@suse.de> Date: Tue, 4 Jun 2019 23:24:09 +0800 Subject: [PATCH] bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached When people set a writeback percent via sysfs file, /sys/block/bcache<N>/bcache/writeback_percent current code directly sets BCACHE_DEV_WB_RUNNING to dc->disk.flags and schedules kworker dc->writeback_rate_update. If there is no cache set attached to, the writebac kernel thread is not running indeed, running dc->writeback_rate_update does not make sense and may cause NULL pointer deference when reference cache set pointer inside update_writeback_rate(). This patch checks whether the cache set point (dc->disk.c) is NULL in sysfs interface handler, and only set BCACHE_DEV_WB_RUNNING and schedule dc->writeback_rate_update when dc->disk.c is not NULL (it means the cache device is attached to a cache set). Reported-by: Bjørn Forsman <bjorn.forsman@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> --- drivers/md/bcache/sysfs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 129031663cc8..eb678e43ac00 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -430,8 +430,13 @@ STORE(bch_cached_dev) bch_writeback_queue(dc); } + /* + * Only set BCACHE_DEV_WB_RUNNING when cached device attached to + * a cache set, otherwise it doesn't make sense. + */ if (attr == &sysfs_writeback_percent) - if (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) + if ((dc->disk.c != NULL) && + (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))) schedule_delayed_work(&dc->writeback_rate_update, dc->writeback_rate_update_seconds * HZ); -- 2.16.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: bcache: oops when writing to writeback_percent without a cache device 2019-06-04 15:41 ` Coly Li @ 2019-06-04 17:24 ` Bjørn Forsman 2019-06-05 4:41 ` Coly Li 0 siblings, 1 reply; 6+ messages in thread From: Bjørn Forsman @ 2019-06-04 17:24 UTC (permalink / raw) To: Coly Li; +Cc: Kent Overstreet, linux-bcache, LKML On Tue, 4 Jun 2019 at 17:41, Coly Li <colyli@suse.de> wrote: > > On 2019/6/4 10:59 下午, Coly Li wrote: > > On 2019/6/4 7:00 下午, Bjørn Forsman wrote: > >> Hi all, > >> > >> I get a kernel oops from bcache when writing to > >> /sys/block/bcache0/bcache/writeback_percent and there is no attached > >> cache device. See the oops itself below my signature. > >> > >> This is on Linux 4.19.46. I looked in git and see many commits to > >> bcache lately, but none seem to address this particular issue. > >> > >> Background: I'm writing to .../writeback_percent with > >> systemd-tmpfiles. I'd rather not replace it with a script that figures > >> out whether or not the kernel will oops if writing to the sysfs file > >> -- the kernel should not oops in the first place. > > > > Hi Bjorn, > > > > Thank you for the reporting. I believe this is a case we missed in > > testings. When a bcache device is not attached, it does not make sense > > to update the writeback rate in period by the changing of writeback_percent. > > > > I will post a patch for your testing soon. > > Hi Bjorn, > > Could you please to try this patch ? Hope it may help a bit. Hi Coly, Thanks for the quick patch! I tested it on linux 5.2-rc2 and it indeed fixes the problem. There is one typo in the patch/commit message: s/writebac/writeback/ -- Best regards, Bjørn Forsman ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: bcache: oops when writing to writeback_percent without a cache device 2019-06-04 17:24 ` Bjørn Forsman @ 2019-06-05 4:41 ` Coly Li 2019-06-05 9:21 ` Bjørn Forsman 0 siblings, 1 reply; 6+ messages in thread From: Coly Li @ 2019-06-05 4:41 UTC (permalink / raw) To: Bjørn Forsman; +Cc: Kent Overstreet, linux-bcache, LKML On 2019/6/5 1:24 上午, Bjørn Forsman wrote: > On Tue, 4 Jun 2019 at 17:41, Coly Li <colyli@suse.de> wrote: >> >> On 2019/6/4 10:59 下午, Coly Li wrote: >>> On 2019/6/4 7:00 下午, Bjørn Forsman wrote: >>>> Hi all, >>>> >>>> I get a kernel oops from bcache when writing to >>>> /sys/block/bcache0/bcache/writeback_percent and there is no attached >>>> cache device. See the oops itself below my signature. >>>> >>>> This is on Linux 4.19.46. I looked in git and see many commits to >>>> bcache lately, but none seem to address this particular issue. >>>> >>>> Background: I'm writing to .../writeback_percent with >>>> systemd-tmpfiles. I'd rather not replace it with a script that figures >>>> out whether or not the kernel will oops if writing to the sysfs file >>>> -- the kernel should not oops in the first place. >>> >>> Hi Bjorn, >>> >>> Thank you for the reporting. I believe this is a case we missed in >>> testings. When a bcache device is not attached, it does not make sense >>> to update the writeback rate in period by the changing of writeback_percent. >>> >>> I will post a patch for your testing soon. >> >> Hi Bjorn, >> >> Could you please to try this patch ? Hope it may help a bit. > > Hi Coly, > > Thanks for the quick patch! I tested it on linux 5.2-rc2 and it indeed > fixes the problem. > > There is one typo in the patch/commit message: s/writebac/writeback/ > Hi Bjorn, Thanks for the patch review. Do you mind if I add Reviewed-By: tag with your name and email address ? -- Coly Li ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: bcache: oops when writing to writeback_percent without a cache device 2019-06-05 4:41 ` Coly Li @ 2019-06-05 9:21 ` Bjørn Forsman 0 siblings, 0 replies; 6+ messages in thread From: Bjørn Forsman @ 2019-06-05 9:21 UTC (permalink / raw) To: Coly Li; +Cc: Kent Overstreet, linux-bcache, LKML On Wed, 5 Jun 2019 at 06:41, Coly Li <colyli@suse.de> wrote: > > On 2019/6/5 1:24 上午, Bjørn Forsman wrote: > > On Tue, 4 Jun 2019 at 17:41, Coly Li <colyli@suse.de> wrote: > >> > >> On 2019/6/4 10:59 下午, Coly Li wrote: > >>> On 2019/6/4 7:00 下午, Bjørn Forsman wrote: > >>>> Hi all, > >>>> > >>>> I get a kernel oops from bcache when writing to > >>>> /sys/block/bcache0/bcache/writeback_percent and there is no attached > >>>> cache device. See the oops itself below my signature. > >>>> > >>>> This is on Linux 4.19.46. I looked in git and see many commits to > >>>> bcache lately, but none seem to address this particular issue. > >>>> > >>>> Background: I'm writing to .../writeback_percent with > >>>> systemd-tmpfiles. I'd rather not replace it with a script that figures > >>>> out whether or not the kernel will oops if writing to the sysfs file > >>>> -- the kernel should not oops in the first place. > >>> > >>> Hi Bjorn, > >>> > >>> Thank you for the reporting. I believe this is a case we missed in > >>> testings. When a bcache device is not attached, it does not make sense > >>> to update the writeback rate in period by the changing of writeback_percent. > >>> > >>> I will post a patch for your testing soon. > >> > >> Hi Bjorn, > >> > >> Could you please to try this patch ? Hope it may help a bit. > > > > Hi Coly, > > > > Thanks for the quick patch! I tested it on linux 5.2-rc2 and it indeed > > fixes the problem. > > > > There is one typo in the patch/commit message: s/writebac/writeback/ > > > > Hi Bjorn, > > Thanks for the patch review. Do you mind if I add Reviewed-By: tag with > your name and email address ? Yes, you can add my Reviewed-By: tag. -- Bjørn Forsman ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-06-05 9:22 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-06-04 11:00 bcache: oops when writing to writeback_percent without a cache device Bjørn Forsman 2019-06-04 14:59 ` Coly Li 2019-06-04 15:41 ` Coly Li 2019-06-04 17:24 ` Bjørn Forsman 2019-06-05 4:41 ` Coly Li 2019-06-05 9:21 ` Bjørn Forsman
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