On the debian buildd servers for the parisc architecture I'm facing the following warning, after which it gets stuck so that I need to reboot the server. This happens rarely, but I can reproduce it after some time. Filesystem is tmpfs. I'm happy to add debug code if necessary... Helge [128321.224739] ------------[ cut here ]------------ [128321.283492] WARNING: CPU: 1 PID: 14735 at fs/dcache.c:365 dentry_free+0x100/0x128 [128321.371369] Modules linked in: dm_mod(E) ipt_REJECT(E) nf_reject_ipv4(E) xt_multiport(E) nft_compat(E) nf_tables(E) nfnetlink(E) ipmi_si(E) ipmi_devintf(E) sg(E) ipmi_msghandler(E) fuse(E) configfs(E) sunrpc(E) ip_tables(E) x_tables(E) autofs4(E) ext4(E) crc16(E) mbcache(E) jbd2(E) btrfs(E) blake2b_generic(E) xor(E) raid6_pq(E) zstd_compress(E) libcrc32c(E) crc32c_generic(E) sd_mod(E) t10_pi(E) crc64_rocksoft(E) crc64(E) crc_t10dif(E) crct10dif_generic(E) ohci_pci(E) crct10dif_common(E) ata_generic(E) sata_sil(E) ehci_pci(E) pata_sil680(E) mptspi(E) mptscsih(E) ohci_hcd(E) mptbase(E) scsi_transport_spi(E) ehci_hcd(E) libata(E) scsi_mod(E) usbcore(E) e1000(E) usb_common(E) scsi_common(E) [128322.103374] CPU: 1 PID: 14735 Comm: cc1plus Tainted: G E 5.18.9+ #27 [128322.195315] Hardware name: 9000/785/C8000 [128322.247318] [128322.263314] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI [128322.323316] PSW: 00001000000001101111000000001111 Tainted: G E [128322.407315] r00-03 000000000806f00f 0000000239aa8700 000000004073be90 0000000239aa87a0 [128322.507313] r04-07 00000000410e1a00 000000411c8e3b40 0000000211715ad8 000000411c8e3b98 [128322.603314] r08-11 00000000410b8e80 0000000041147200 00000000000800e0 0000000041147200 [128322.699311] r12-15 0000000000000001 0000000010000000 0000000041147200 0000000041147200 [128322.795312] r16-19 000000411c8e3b98 0000000000000000 00000000415084d0 0000000002c55000 [128322.895311] r20-23 000000000800000f 000000004fb33600 000000000800000f 0000000211715b20 [128322.991311] r24-27 000000411c8e3bd0 000000411c8e3bd0 000000411c8e3b40 00000000410e1a00 [128323.087309] r28-31 00000000416bf9d8 0000000239aa8770 0000000239aa8820 000000000000cf14 [128323.187310] sr00-03 000000000500a800 0000000000000000 0000000000000000 000000000500a800 [128323.283324] sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [128323.383313] [128323.399309] IASQ: 0000000000000000 0000000000000000 IAOQ: 000000004073b3d4 000000004073b3d8 [128323.503310] IIR: 03ffe01f ISR: 0000000010340400 IOR: 000003e6aa2a87a8 [128323.587306] CPU: 1 CR30: 0000000212ff0ce0 CR31: ffffffffffffffff [128323.667328] ORIG_R28: 0000000239aa8920 [128323.715307] IAOQ[0]: dentry_free+0x100/0x128 [128323.771306] IAOQ[1]: dentry_free+0x104/0x128 [128323.823305] RP(r2): __dentry_kill+0x284/0x2e8 [128323.875347] Backtrace: [128323.907319] [<000000004073be90>] __dentry_kill+0x284/0x2e8 [128323.975309] [<000000004073d6d8>] dput+0x334/0x5a8 [128324.031311] [<0000000040726d94>] step_into+0x790/0xa88 [128324.095309] [<0000000040728910>] path_openat+0x21c/0x1ba8 [128324.163310] [<000000004072c018>] do_filp_open+0x9c/0x198 [128324.231310] [<0000000040702320>] do_sys_openat2+0x14c/0x2a8 [128324.299309] [<0000000040702c54>] compat_sys_openat+0x58/0xb8 [128324.367308] [<0000000040303e30>] syscall_exit+0x0/0x10 after that: [128324.451303] ---[ end trace 0000000000000000 ]--- [128345.511159] rcu: INFO: rcu_sched self-detected stall on CPU [128345.511159] rcu: 0-...!: (5249 ticks this GP) idle=3c3/1/0x4000000000000002 softirq=35954078/35954078 fqs=54 [128345.511159] (t=5250 jiffies g=33838821 q=175418) [128345.511159] rcu: rcu_sched kthread starved for 5146 jiffies! g33838821 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 [128345.511159] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. [128345.511159] ... [128345.511159] [128345.511159] rcu: Stack dump where RCU GP kthread last ran: [128345.511159] Task dump for CPU 1: [128345.511159] task:cc1plus state:R running task stack: 0 pid:14735 ppid: 14734 flags:0x00000014 [128345.511159] Backtrace: [128345.511159] [<000000004071f5c8>] __legitimize_path+0x7c/0x108 [128345.511159] [<00000000407210d4>] lookup_fast+0x1c8/0x290 [128345.511159] [<00000000407277b4>] walk_component+0x1e8/0x330 [128345.511159] [<0000000040727be8>] link_path_walk.part.0.constprop.0+0x2ec/0x4d0 [128345.511159] [<0000000040728844>] path_openat+0x150/0x1ba8 [128345.511159] [<000000004072c018>] do_filp_open+0x9c/0x198 [128345.511159] [<0000000040702320>] do_sys_openat2+0x14c/0x2a8 [128345.511159] [<0000000040702c54>] compat_sys_openat+0x58/0xb8 [128345.511159] [<0000000040303e30>] syscall_exit+0x0/0x10 [128345.511159]
