From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48285C94.6070204@oracle.com> Date: Mon, 12 May 2008 08:04:52 -0700 From: Randy Dunlap MIME-Version: 1.0 Subject: Re: BUG: 2.6.26-rc1-git8: NULL reference in drop_buffers References: <20080511105429.a5e40721.randy.dunlap@oracle.com> <20080511232344.b173ca9f.akpm@linux-foundation.org> In-Reply-To: <20080511232344.b173ca9f.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: lkml , viro , Jan Kara , linux-mm@kvack.org List-ID: Andrew Morton wrote: > On Sun, 11 May 2008 10:54:29 -0700 Randy Dunlap wrote: > >> On x86_64, during testing using "stress" package: >> >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > > >> IP: [] drop_buffers+0x2f/0xfb >> PGD 1ee8ad067 PUD 26f19a067 PMD 0 >> Oops: 0000 [1] SMP >> CPU 3 >> Modules linked in: parport_pc lp parport tg3 cciss ehci_hcd ohci_hcd uhci_hcd >> Pid: 16860, comm: stress Not tainted 2.6.26-rc1-git8 #1 >> RIP: 0010:[] [] drop_buffers+0x2f/0xfb >> RSP: 0000:ffff81026bc03a08 EFLAGS: 00010203 >> RAX: 0000000000000000 RBX: ffffe20008bae680 RCX: ffff81027f490f00 >> RDX: 0000000000000000 RSI: ffff81026bc03a58 RDI: ffffe20008bae680 >> RBP: ffff81026bc03a38 R08: ffff81026bc03b78 R09: ffff810001103780 >> R10: ffff81026bc03a08 R11: ffff81026bc03c88 R12: ffffe20008bae680 >> R13: ffff81027c412850 R14: ffff81026bc03d58 R15: ffff81026bc03a58 >> FS: 00007fa9e7e416f0(0000) GS:ffff81027f806980(0000) knlGS:00000000f7f856c0 >> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b >> CR2: 0000000000000000 CR3: 000000027f973000 CR4: 00000000000006e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 >> Process stress (pid: 16860, threadinfo ffff81026bc02000, task ffff81027e424c50) >> Stack: ffffe20008bafa68 ffffe20008bae680 ffff81027f490f00 ffff81026bc03a58 >> ffff81026bc03d58 ffff81026bc03c88 ffff81026bc03a78 ffffffff802ad39f >> ffff81027f490f00 ffffe20008b14060 0000000000000000 ffff81027f490f00 >> Call Trace: >> [] try_to_free_buffers+0x60/0xa2 >> [] try_to_release_page+0x3b/0x41 >> [] shrink_page_list+0x457/0x562 >> [] shrink_inactive_list+0x126/0x361 >> [] shrink_zone+0xe5/0x10a >> [] try_to_free_pages+0x1ef/0x326 >> [] ? isolate_pages_global+0x0/0x34 >> [] __alloc_pages_internal+0x25a/0x3ad >> [] __alloc_pages+0xb/0xd >> [] handle_mm_fault+0x238/0x6d0 >> [] do_page_fault+0x438/0x7de >> [] error_exit+0x0/0x51 >> >> >> Code: 41 57 49 89 f7 41 56 41 55 41 54 49 89 fc 53 48 83 ec 08 48 8b 07 25 00 08 00 00 48 85 c0 75 04 0f 0b eb fe 4c 8b 6f 10 4c 89 ea <48> 8b 02 25 00 08 00 00 48 85 c0 74 10 49 8b 44 24 18 48 85 c0 >> RIP [] drop_buffers+0x2f/0xfb >> RSP >> CR2: 0000000000000000 >> Kernel panic - not syncing: Fatal exception > > Seems that local variable `bh' is NULL. > > I wonder what the heck we did to cause that. Which filesystems were in > use? ext3, nfs, and the usual procfs, sysfs, and tmpfs. Also in the kernel: debugfs, usbfs, inotifyfs, configfs, ramfs, hugetlbfs, msdos, vfat, iso9660, and rootfs. -- ~Randy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org