2.6.30-stable review patch. If anyone has any objections, please let us know. ------------------ From: KAMEZAWA Hiroyuki Not upstream due to other fixes in .32 Works around a BUG() which is triggered when the kernel accesses holes in vmalloc regions. BUG: unable to handle kernel paging request at fa54c000 IP: [] read_kcore+0x260/0x31a *pde = 3540b067 *pte = 00000000 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/pci0000:00/0000:00:1c.2/0000:03:00.0/ieee80211/phy0/rfkill0/state Modules linked in: fuse sco bridge stp llc bnep l2cap bluetooth sunrpc nf_conntrack_ftp ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 cpufreq_ondemand acpi_cpufreq dm_multipath uinput usb_storage arc4 ecb snd_hda_codec_realtek snd_hda_intel ath5k snd_hda_codec snd_hwdep iTCO_wdt snd_pcm iTCO_vendor_support pcspkr i2c_i801 mac80211 joydev snd_timer serio_raw r8169 snd soundcore mii snd_page_alloc ath cfg80211 ata_generic i915 drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan] Sep 4 12:45:16 tuxedu kernel: Pid: 2266, comm: cat Not tainted (2.6.31-rc8 #2) Joybook Lite U101 EIP: 0060:[] EFLAGS: 00010286 CPU: 0 EIP is at read_kcore+0x260/0x31a EAX: f5e5ea00 EBX: fa54d000 ECX: 00000400 EDX: 00001000 ESI: fa54c000 EDI: f44ad000 EBP: e4533f4c ESP: e4533f24 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process cat (pid: 2266, ti=e4532000 task=f09d19a0 task.ti=e4532000) Stack: 00005000 00000000 f44ad000 09d9c000 00003000 fa54c000 00001000 f6d16f60 e4520b80 fffffffb e4533f70 c04ef8eb e4533f98 00008000 09d97000 c04f661a e4520b80 09d97000 c04ef88c e4533f8c c04ba531 e4533f98 c04c0930 e4520b80 Call Trace: [] ? proc_reg_read+0x5f/0x73 [] ? read_kcore+0x0/0x31a [] ? proc_reg_read+0x0/0x73 [] ? vfs_read+0x82/0xe1 [] ? path_put+0x1a/0x1d [] ? sys_read+0x40/0x62 [] ? sysenter_do_call+0x12/0x2d Code: 39 f3 89 ca 0f 43 f3 89 fb 29 f2 29 f3 39 cf 0f 46 d3 29 55 dc 8d 1c 32 f6 40 0c 01 75 18 89 d1 89 f7 c1 e9 02 2b 7d ec 03 7d e0 a5 89 d1 83 e1 03 74 02 f3 a4 8b 00 83 7d dc 00 74 04 85 c0 EIP: [] read_kcore+0x260/0x31a SS:ESP 0068:e4533f24 CR2: 00000000fa54c000 To access vmalloc area which may have memory holes, copy_from_user is useful. So this: # cat /proc/kcore > /dev/null will not panic. This is a minimal fix, suitable for 2.6.30.x and 2.6.31. More extensive /proc/kcore changes are planned for 2.6.32. Signed-off-by: KAMEZAWA Hiroyuki Tested-by: Nick Craig-Wood Cc: Pekka Enberg Reported-by: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/proc/kcore.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -361,7 +361,13 @@ read_kcore(struct file *file, char __use /* don't dump ioremap'd stuff! (TA) */ if (m->flags & VM_IOREMAP) continue; - memcpy(elf_buf + (vmstart - start), + /* + * we may access memory holes, then use + * ex_table. checking return value just for + * avoid warnings. + */ + vmsize = __copy_from_user_inatomic( + elf_buf + (vmstart - start), (char *)vmstart, vmsize); } read_unlock(&vmlist_lock); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/