Hi I hit a bug in ext4 - jbd2 was stuck in an infinite loop when remounting the root filesystem read-only during shutdown. The filesystem is ext3, but it uses the ext4 driver with the following options: rw,relatime,discard,errors=remount-ro,data=ordered The machine was stuck, but it was possible to obtain a stacktrace with Alt-SysRQ-P. I put several stacktraces here: http://people.redhat.com/~mpatocka/crashes/ext4/ The stacktraces change in jbd2_log_do_checkpoint and jbd2_cleanup_journal_tail. jbd2_log_do_checkpoint doesn't call jbd2_cleanup_journal_tail from a loop, so the the probable location of the infinite loop was this piece of code in jbd2_journal_flush: while (!err && journal->j_checkpoint_transactions != NULL) { Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html