Hi folks, I just saw an ext4 oops on one of my machines after a couple months of uptime, on Linux 3.5.2. I doubt I will be able to reproduce the problem easily so I'm just posting this in case anyone can tell what's going on. Going by the timing, and the call trace, it is presumably related to the fact that I had rm'd a ~12G file shortly before the last log entry. The filesystem is aged somewhat and close to full (hence why I was deleting the file in the first place). However, I'm not certain of the *exact* timeline because I didn't notice that the system had crashed until the next day. In case it matters, fs recovery after resetting the box resulted in hundreds of messages like: EXT4-fs (md127): ext4_orphan_cleanup: deleting unreferenced inode 12058658 I took a photo of the oops text that was on screen and posted it here: http://i.imgur.com/7DfIP.jpg For convenience (and the benefit of list archives), I've transcribed the oops, but I could have easily fat-fingered something so the only the photo is authoritative. BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 IP: [<ffffffffa007b332>] ext4_ext_remove_space+0x725/0x9db [ext4] PGD 1043f067 PUD 1078f067 PMD 0 Oops: 0000 [#1] PREEMPT CPU 0 Modules linked in: nls_iso8859_1 nls_cp437 vfat fat usb_storage nls_utf8 isofs it87 hwmon_vid sha1_generic hmac aes_generic cbc cts crypto_blkcipher cryptomgr aead nfs nfsd exportfs lockd bridge stp ipv6 llc iptable_filter iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack ip_tables x_tables ext2 snd_pcm_oss snd_mixer_oss snd_emu10k1_synth snd_emux_synth snd_seq_midi_emul snd_seq_virmidi snd_seq_midi_event snd_seq rpcsec_gss_krb5 auth_rpcgss sunrpc tun raid456 async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx sg firewire_sbp2 loop snd_emu10k1 sr_mod snd_hwdep snd_util_mem snd_ac97_codec ac9_bus snd_rawmidi snd_seq_device snd_pcm snd_page_alloc snd_timer snd ftdi_sio cdrom epic100 firewire_ohci emu10k1_gp firewire_core gameport crc_itu_t soundcore forcedeth k8temp usbserial mii powernow_k8 floppy pata_amd mperf evdev i2c_nforce2 ext4 crc16 jbd2 crypto_hash crypto_algapi crypto mbcache raid1 md_mod Pid: 13628, comm: rm Not tainted 3.5.2 #107 ASUSTek Computer Inc. K8N-E-Deluxe/'K8N-E-Deluxe' RIP: 0010:[<ffffffffa007b332>] [<ffffffffa007b332>] ext4_ext_remove_space+0x725/0x9db [ext4] RSP: 0018:ffff8800105cfca8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88006d5db5f0 RCX: 0000000000000002 RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000073f313e RBP: ffff8800105cfd88 R08: 00000000073f313e R09: 00000000000003e8 R10: 0000160000000000 R11: ffff88007b930180 R12: ffff8800588e4d68 R13: ffff88004d002000 R14: ffff88006d5db5c0 R15: 0000000000000000 FS: 00007f1e400b8700(0000) GS:ffffffff81623000(0000) knlGS:00000000f757a6c0 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000028 CR3: 000000007c6ec000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process rm (pid: 13628, threadinfo ffff8800105ce00, task ffff8800718e7230) Stack: ffff88000133bde0 ffff8800588e4d68 ffff8800219d2300 ffff880017ebf3d8 ffff8800105cfd50 0000000000000003 0000000004549000 ffff8800fffffff5 ffffffff105cfd50 ffff88006d5db648 ffff8800588e4cc8 0000080080006a88 Call Trace: [<ffffffffa007cd29>] ext4_ext_truncate+0xcd/0x173 [ext4] [<ffffffffa006875a>] ? ext4_mark_inode_dirty+0x13e/0x168 [ext4] [<ffffffffa0066417>] ext4_truncate+0x46/0x51 [ext4] [<ffffffffa006a0d2>] ext4_evict_inode+0x276/0x363 [ext4] [<ffffffffa0069e5c>] ? ext4_da_writepages+0x423/0x423 [ext4] [<ffffffff810a4b70>] evict+0xb6/0x182 [<ffffffff810a51dd>] iput+0x1fb/0x203 [<ffffffff8109b526>] do_unlinkat+0x10b/0x161 [<ffffffff8109c762>] sys_unlinkat+0x24/0x26 [<ffffffff8132ff64>] system_call_fastpath+0x1a/0x1f Code: e1 ff ff 48 63 5d bc 48 6b db 30 48 03 5d b0 e9 f1 00 00 00 48 63 55 bc 48 6b da 30 48 03 5d b0 48 83 7b 20 00 75 0c 48 8b 43 28 <48> 8b 40 28 48 89 43 20 48 8b 43 18 48 85 c0 75 1f 48 8b 43 20 RIP [<ffffffffa007b332>] ext4_ext_remove_space+0x725/0x9db [ext4] RSP <ffff8800105cfca8> CR2: 0000000000000028 Thanks, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
