Hello, Today my red hat 7.2 linux server froze I killed the power and rebooted and all seems fine but why did it happen? Here is what I obtained from /var/log/messages

Oct 22 13:21:29 ALS2 kernel: Assertion failure in journal_commit_transaction() at commit.c:535: "buffer_jdirty(bh)"
Oct 22 13:21:29 ALS2 kernel: ------------[ cut here ]------------
Oct 22 13:21:29 ALS2 kernel: kernel BUG at commit.c:535!
Oct 22 13:21:29 ALS2 kernel: invalid operand: 0000
Oct 22 13:21:29 ALS2 kernel: aic7xxx nls_iso8859-1 vfat fat ide-cd cdrom st autofs tg3 e1000 ipchains usb-o
Oct 22 13:21:29 ALS2 kernel: CPU: 1
Oct 22 13:21:29 ALS2 kernel: EIP: 0010:[<f883d0e4>] Tainted: P
Oct 22 13:21:29 ALS2 kernel: EFLAGS: 00010286
Oct 22 13:21:29 ALS2 kernel:
Oct 22 13:21:29 ALS2 kernel: EIP is at journal_commit_transaction [jbd] 0xb04 (2.4.18-3smp)
Oct 22 13:21:29 ALS2 kernel: eax: 0000001c ebx: 0000000a ecx: c02eee60 edx: 000073b8
Oct 22 13:21:29 ALS2 kernel: esi: e78e3f40 edi: f73dcec0 ebp: f73f2000 esp: f73f3e78
Oct 22 13:21:29 ALS2 kernel: ds: 0018 es: 0018 ss: 0018
Oct 22 13:21:29 ALS2 kernel: Process kjournald (pid: 19, stackpage=f73f3000)
Oct 22 13:21:29 ALS2 kernel: Stack: f8843eee 00000217 f7411e6c 00000000 000003ac e3217c54 00000000 f1e34a40
Oct 22 13:21:29 ALS2 kernel: cf51d5b0 000006e2 00000286 00000286 00000001 f7fbae60 e4ca8ae0 f4b874e0
Oct 22 13:21:29 ALS2 kernel: f4b87840 f4b877e0 f4b871e0 f4b875a0 f4b876c0 f4b87420 c98f3680 e8d766e0
Oct 22 13:21:29 ALS2 kernel: Call Trace: [<f8843eee>] .rodata.str1.1 [jbd] 0x26e
Oct 22 13:21:29 ALS2 kernel: [<c012130b>] bh_action [kernel] 0x4b
Oct 22 13:21:29 ALS2 kernel: [<c01211bc>] tasklet_hi_action [kernel] 0x6c
Oct 22 13:21:29 ALS2 kernel: [<c0120f3b>] do_softirq [kernel] 0x7b
Oct 22 13:21:29 ALS2 kernel: [<c010a77f>] do_IRQ [kernel] 0xdf
Oct 22 13:21:29 ALS2 kernel: [<c0119048>] schedule [kernel] 0x348
Oct 22 13:21:29 ALS2 kernel: [<f883f7d6>] kjournald [jbd] 0x136
Oct 22 13:21:29 ALS2 kernel: [<f883f680>] commit_timeout [jbd] 0x0
Oct 22 13:21:29 ALS2 kernel: [<c0107286>] kernel_thread [kernel] 0x26
Oct 22 13:21:29 ALS2 kernel: [<f883f6a0>] kjournald [jbd] 0x0
Oct 22 13:21:29 ALS2 kernel:
Oct 22 13:21:29 ALS2 kernel:
Oct 22 13:21:29 ALS2 kernel: Code: 0f 0b 5a 59 6a 04 8b 44 24 18 50 56 e8 4b f1 ff ff 8d 47 48

If the kernel version is less or equal to 2.4.19, upgrade to a higher one like RH's 2.4.20 should fix this. Force verifying all your filesystems if you didn't already.