Description of problem: Shrinking device size with outstanding io requests can cause kernel panic. See Jun'ichi Nomura's patch proposal http://lkml.org/lkml/2007/10/30/432 (reproducer script inside) BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024 printing eip: d092740f *pde = 00000000 Oops: 0000 [#1] SMP last sysfs file: /block/loop0/range Modules linked in: loop autofs4 hidp rfcomm l2cap bluetooth sunrpc ipv6 dm_multipath video sbs backlight i2c_ec button battery asus_acpi ac lp ata_piix lib CPU: 0 EIP: 0060:[<d092740f>] Not tainted VLI EFLAGS: 00010202 (2.6.18-52.el5 #1) EIP is at __map_bio+0x41/0x10a [dm_mod] eax: d0abc0c0 ebx: 00000000 ecx: c8642810 edx: c8b60bc0 esi: c8b60bc0 edi: c8642808 ebp: d0abc0c0 esp: c8b68d5c ds: 007b es: 007b ss: 0068 Process dmsetup (pid: 2543, ti=c8b68000 task=c8b6caa0 task.ti=c8b68000) Stack: 00000001 00000000 c8b60bc0 c04743d3 00000010 00000000 c8b60bc0 cfeb4e00 00000200 c8642808 d0927fa4 cdbbae40 c8b7eac0 00000007 00000000 ffffffff ffffffff 00000007 00000000 00000200 d0abc0c0 cfeb4e00 00000000 00000000 Call Trace: [<c04743d3>] bio_alloc_bioset+0x9b/0xf3 [<d0927fa4>] __split_bio+0x3bc/0x418 [dm_mod] [<d0928017>] __flush_deferred_io+0x17/0x20 [dm_mod] [<d0928132>] dm_resume+0x78/0xda [dm_mod] [<d092abb9>] dev_suspend+0x133/0x152 [dm_mod] [<d092b335>] ctl_ioctl+0x1f3/0x238 [dm_mod] [<d092aa86>] dev_suspend+0x0/0x152 [dm_mod] [<c047f213>] do_ioctl+0x47/0x5d [<c047f473>] vfs_ioctl+0x24a/0x25c [<c047f4cd>] sys_ioctl+0x48/0x5f [<c0404eff>] syscall_call+0x7/0xb ======================= Code: 02 64 c9 92 d0 c7 46 34 d8 74 92 d0 89 7e 3c 8b 07 90 ff 40 0c 8b 06 8d 4f 08 8b 56 04 89 04 24 89 e8 89 54 24 04 8b 5d 04 89 f2 <ff> 53 24 83 f8 01 EIP: [<d092740f>] __map_bio+0x41/0x10a [dm_mod] SS:ESP 0068:c8b68d5c <0>Kernel panic - not syncing: Fatal exception
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
in 2.6.18-61.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2008-0314.html