Messages in this thread Patch in this message | | | Date | Tue, 19 Jul 2022 16:59:21 -0400 | Subject | Re: WARNING: CPU: 1 PID: 14735 at fs/dcache.c:365 dentry_free+0x100/0x128 | From | John David Anglin <> |
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Hi Helge,
I hit this warning with the patch below building ghc on mx3210:
mx3210 login: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 32654 at fs/dcache.c:365 dentry_free+0xfc/0x108 Modules linked in: binfmt_misc ext2 ext4 crc16 mbcache jbd2 ipmi_watchdog sg ipmi_si ipmi_poweroff ipmi_devintf ipmi_msghandler fuse nfsd ip_tables x_tables ipv6 autofs4 xfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod t10_pi ses enclosure scsi_transport_sas crc64_rocksoft crc64 uas usb_storage sr_mod cdrom ohci_pci sym53c8xx pata_cmd64x ehci_pci ohci_hcd libata scsi_transport_spi ehci_hcd tg3 scsi_mod usbcore scsi_common usb_common CPU: 2 PID: 32654 Comm: cc1 Not tainted 5.18.12+ #2 Hardware name: 9000/800/rp3440
YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001000110100000001111 Not tainted r00-03 000000000804680f 00000040ce7fc880 00000000404f2b74 00000040ce7fc920 r04-07 0000000040be4940 000000410f6cd630 00000001413e4068 000000410f6cd688 r08-11 0000000040fd2e60 0000000040bc5020 0000000040c2c940 00000000000800e0 r12-15 0000000040c2c940 0000000000000001 0000000040c2c940 000000410f6cd688 r16-19 00000001f9fe105d 00000040ce7fc1f8 000000000000002f 000000000a0c1000 r20-23 000000000800000f 000000000800000f 000000410f6cd639 000000000800000f r24-27 0000000000000000 0000000000000385 000000410f6cd630 0000000040be4940 r28-31 0000000041104530 00000040ce7fc8f0 00000040ce7fc9a0 0000000000000000 sr00-03 0000000000a03800 0000000000000000 0000000000000000 0000000000a03800 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000
IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000404f18bc 00000000404f18c0 IIR: 03ffe01f ISR: 0000000010350000 IOR: 00000239ff3fc928 CPU: 2 CR30: 00000040cadd1380 CR31: ffffffffffffffff ORIG_R28: 00000040ce7fcb70 IAOQ[0]: dentry_free+0xfc/0x108 IAOQ[1]: dentry_free+0x100/0x108 RP(r2): __dentry_kill+0x2bc/0x338 Backtrace: [<00000000404f2b74>] __dentry_kill+0x2bc/0x338 [<00000000404f37b8>] dentry_kill+0xb0/0x318 [<00000000404f3d08>] dput+0x2e8/0x328 [<00000000404dd7dc>] step_into+0x344/0x390 [<00000000404dda4c>] walk_component+0xa4/0x310 [<00000000404df234>] link_path_walk.part.0+0x2ec/0x4b0 [<00000000404e0000>] path_openat+0xe8/0x348 [<00000000404e2c58>] do_filp_open+0x98/0x178 [<00000000404babe8>] do_sys_openat2+0x148/0x288 [<00000000404bb41c>] compat_sys_openat+0x54/0x98 [<0000000040203e30>] syscall_exit+0x0/0x10
---[ end trace 0000000000000000 ]--- watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [cc1:32657]
Regards, Dave
On 2022-07-19 12:32 p.m., Helge Deller wrote: > Hello Hillf, > > On 7/17/22 13:36, Hillf Danton wrote: >> On Sun, 17 Jul 2022 11:42:48 +0200 >>> I used WARN_ON() instead of BUG_ON(). >>> With that, both triggered, first the first one, then the second one. >>> Full log is here: >>> http://dellerweb.de/testcases/minicom.dcache.crash.6-warn >> Given the first BUG_ON triggered, and dentry at the moment is supposed to >> not be alias, see if it is still in lookup with d_lock held. That is the >> step before de-unioning d_alias with d_in_lookup_hash. >> >> On the other hand if only the second one triggered, we should track >> DCACHE_DENTRY_KILLED instead in assumption that killed dentry was >> used again after releasing d_lock surrounding the firt one. > The machine has now been up for 2 days without any issues, while it had pretty > much the same load as when it was crashing earlier. > So, in summary I'd assume that your patch below fixes the issue. > > I'm now rebooting the machine with a new kernel, where I just changed > if (unlikely(d_in_lookup(dentry))) > to > if (WARN_ON_ONCE(d_in_lookup(dentry))) > in order to see if this really triggered. > > Anyway, I think your patch is good so far. > Would that be the final patch, or should I test some others? > > Thanks! > Helge > >> --- a/fs/dcache.c >> +++ b/fs/dcache.c >> @@ -605,8 +605,12 @@ static void __dentry_kill(struct dentry >> spin_unlock(&parent->d_lock); >> if (dentry->d_inode) >> dentry_unlink_inode(dentry); >> - else >> + else { >> + if (unlikely(d_in_lookup(dentry))) { >> + __d_lookup_done(dentry); >> + } >> spin_unlock(&dentry->d_lock); >> + } >> this_cpu_dec(nr_dentry); >> if (dentry->d_op && dentry->d_op->d_release) >> dentry->d_op->d_release(dentry);
-- John David Anglin dave.anglin@bell.net
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