http://bugzilla.kernel.org/show_bug.cgi?id=15230 URL: http://lxr.linux.no/linux+v2.6.31/fs/ext4/super.c#L146 8 Summary: oops on ext4 remount with -o barrier Product: File System Version: 2.5 Kernel Version: 2.6.31.12 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: ext4 AssignedTo: fs_ext4@xxxxxxxxxxxxxxxxxxxx ReportedBy: stephane_kernel@xxxxxxxxxxx Regression: No I was going to post this on the Fedora bugzilla, but it is also reproductible on Ubuntu. So, here it is: When remounting an ext4 filesystem with -o barrier, the kernel oopses. After a quick look at the kernel source code ( http://lxr.linux.no/linux+v2.6.31/fs/ext4/super.c#L1468 ), the oops seems to happen when trying to parse the mount options, presumably because I specify "barrier" and not "barrier=1" or "barrier=0". On line 1469, if I'm not mistaken, a possible patch would be : -if (match_int(&args[0], &option)) { +if (!args[0] || match_int(&args[0], &option)) { ... absolutely untested. :) Fedora: kernel-PAE-2.6.31.12-174.2.3.fc12.i686 Ubuntu: linux-image-2.6.31-14-generic Steps to Reproduce: 1. dd if=/dev/zero of=/dev/shm/test bs=1M count=32 2. losetup /dev/loop5 /dev/shm/test 3. mkfs.ext4 /dev/loop5 4. mkdir /mnt/test 5. mount /dev/loop5 /mnt/test -o nobarrier # ok 7. mount /mnt/test -o remount,barrier # kernel oops Actual results (on Fedora): BUG: unable to handle kernel NULL pointer dereference at 00000001 IP: [<c05a5f47>] match_number+0x3c/0x8b *pdpt = 0000000007755001 *pde = 00000000419bf067 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu1/cpufreq/scaling_cur_freq Modules linked in: nls_utf8 fuse xt_multiport xt_comment iptable_security iptable_mangle iptable_nat nf_nat iptable_raw cpufreq_stats cpufreq_powersave cpufreq_conservative vboxnetadp vboxnetflt vboxdrv coretemp cpufreq_ondemand acpi_cpufreq xt_physdev ip6t_REJECT ip6t_ipv6header nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 vfat fat ext2 dm_multipath kvm_intel kvm uinput nvidia(P) snd_hda_codec_si3054 snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device mmc_block arc4 ecb snd_pcm snd_timer snd iwl3945 sdhci_pci soundcore sdhci firewire_ohci iwlcore snd_page_alloc mmc_core ricoh_mmc firewire_core iTCO_wdt mac80211 crc_itu_t iTCO_vendor_support uvcvideo i2c_i801 cfg80211 videodev rfkill v4l1_compat tg3 i2c_core wmi joydev tpm_infineon compal_laptop aes_i586 aes_generic xts gf128mul dm_crypt video output [last unloaded: scsi_wait_scan] Pid: 2926, comm: mount Tainted: P (2.6.31.12-174.2.3.fc12.i686.PAE #1) N/A EIP: 0060:[<c05a5f47>] EFLAGS: 00210206 CPU: 0 EIP is at match_number+0x3c/0x8b EAX: 0000000d EBX: cc83be7c ECX: 00000003 EDX: d14a1aa0 ESI: 00000001 EDI: d14a1aa0 EBP: cc83be58 ESP: cc83be3c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process mount (pid: 2926, ti=cc83a000 task=c383b300 task.ti=cc83a000) Stack: 00000000 cc83be94 d14a1aa0 c078fec4 edc0d800 edcd8000 cc83be7c cc83be60 <0> c05a5fbe cc83bea4 c0531e5b 0000000e 00000000 00000000 cb6ce012 00000000 <0> 00000001 0000000e c04a0cfa 00000000 036d8afe 00200246 edcd804c edc0d800 Call Trace: [<c05a5fbe>] ? match_int+0xa/0xc [<c0531e5b>] ? parse_options+0x437/0x69e [<c04a0cfa>] ? generic_writepages+0x1e/0x28 [<c0534bd7>] ? ext4_remount+0xc3/0x38d [<c049caf4>] ? filemap_write_and_wait+0x27/0x32 [<c0534b14>] ? ext4_remount+0x0/0x38d [<c04ca408>] ? do_remount_sb+0xae/0xe5 [<c04dbee5>] ? do_mount+0x262/0x6e4 [<c04a0362>] ? __get_free_pages+0x24/0x26 [<c04dc3cd>] ? sys_mount+0x66/0x98 [<c040909c>] ? syscall_call+0x7/0xb Code: 55 e8 ba d0 00 00 00 89 4d e4 8b 40 04 40 2b 03 e8 de ca f1 -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- 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
