Hi.

Kernel panic occurs because of the combination of cachefilesd and sendmail.

# # This issue was reported to Linux filesystem caching discussion list linux-cachefs@redhat.com #

Confirmed environment: 1, On i386 platform OS : CentOS 5 i386 CPU : Pentium M Mem : 2G Kernel : 2.6.18-8.1.15.el5 #1 SMP Mon Oct 22 08:32:04 EDT 2007 i686 i686 i386 GNU/Linux (Installed by RPM)

2, On X86-64 platform OS : CentOS 5 X86-64 CPU : Opteron (Dual Core) Mem : 16G Kernel : 2.6.18-8.1.15.el5 #1 SMP Mon Oct 22 08:32:28 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux (Installed by RPM)

How To reproduce: 1, Stor OS image to NFS Server. I used CentOS 5.

# mkdir /mnt/nfs # mount -t nfs -o fsc 192.168.1.1:/your/export/dir /mnt/nfs # mkdir /mnt/nfs/centos5 # rsync -axv / /mnt/nfs/centos5

2, Launch sendmail.

# /etc/init.d/sendmail stop <- if running # /etc/init.d/cachefilesd start <- if not running # cd /mnt/nfs/centos5 # chroot . # /etc/init.d/sendmail start # exit <- exit from chroot

3, Connect to sendmail, and occur kernel panic. # telnet localhost smtp

Kernel dumps thi message, and perfectly freeze. (This kernel message is x86-64 platform.)

----------- [cut here ] --------- [please bite here ] --------- Kernel BUG at fs/nfs/fscache.h:267 invalid opcode: 0000 [1] SMP last sysfs file: /class/net/sit0/address CPU 0 Modules linked in: ipv6 nfs lockd nfs_acl sunrpc cachefiles fscache dm_mirror dm_mod video sbs i2c_ec i2c_core button battery asus_acpi acpi_memhotplug ac parport_pc lp parport ide_cd shpchp k8_edac tg3 serio_d Pid: 2402, comm: sendmail Not tainted 2.6.18-8.el5 #1 RIP: 0010:[<ffffffff882eabc8>] [<ffffffff882eabc8>] :nfs:nfs_fscache_release_page+0x1e/0x5e RSP: 0018:ffff81023362bc98 EFLAGS: 00010246 RAX: ffff81023476e308 RBX: ffff810008b4da78 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff81023362bc68 RDI: ffff810008b4da78 RBP: ffff81023476e1f8 R08: 0000000000000001 R09: 0000000000000000 R10: ffff810233a51298 R11: ffffffff882eac08 R12: ffff81023476e308 R13: 0000000000000000 R14: 0000000000000001 R15: ffffffffffffffff FS: 00002aaaada80a80(0000) GS:ffffffff8038a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 000055556fb72d98 CR3: 0000000235244000 CR4: 00000000000006e0 Process sendmail (pid: 2402, threadinfo ffff81023362a000, task ffff81023fbc90c0) Stack: 0000000000000000 ffff810008b4da78 0000000000000000 ffffffff882eac45 0000000000000000 ffff810008b4da78 0000000000000000 ffffffff800bcd28 000000003362bd18 0000000000000000 0000000000000003 0000000000000000 Call Trace: [<ffffffff882eac45>] :nfs:nfs_release_page+0x3d/0x4d [<ffffffff800bcd28>] invalidate_inode_pages2_range+0x122/0x21a [<ffffffff882f435c>] :nfs:nfs_sync_inode_wait+0x116/0x1db [<ffffffff882ed337>] :nfs:nfs_revalidate_mapping+0xac/0x1b4 [<ffffffff882eb2ee>] :nfs:nfs_file_read+0x45/0x97 [<ffffffff8000c8f8>] do_sync_read+0xc7/0x104 [<ffffffff800645d8>] do_page_fault+0x4eb/0x81d [<ffffffff8009b666>] autoremove_wake_function+0x0/0x2e [<ffffffff8000b212>] vfs_read+0xcb/0x171 [<ffffffff80012dbe>] sys_pread64+0x50/0x70 [<ffffffff8005be1d>] error_exit+0x0/0x84 [<ffffffff8005b14e>] system_call+0x7e/0x83

Code: 0f 0b 68 4a c2 30 88 c2 0b 01 8b 03 f6 c4 01 74 0d be 08 00 RIP [<ffffffff882eabc8>] :nfs:nfs_fscache_release_page+0x1e/0x5e RSP <ffff81023362bc98> <0>Kernel panic - not syncing: Fatal exception Nov 1 12:07:17