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Commit 04496411 authored by Tao Ma's avatar Tao Ma Committed by Theodore Ts'o
Browse files

ext4: init timer earlier to avoid a kernel panic in __save_error_info 

During mount, when we fail to open journal inode or root inode, the
__save_error_info will mod_timer. But actually s_err_report isn't
initialized yet and the kernel oops. The detailed information can
be found https://bugzilla.kernel.org/show_bug.cgi?id=32082

.

The best way is to check whether the timer s_err_report is initialized
or not. But it seems that in include/linux/timer.h, we can't find a
good function to check the status of this timer, so this patch just
move the initializtion of s_err_report earlier so that we can avoid
the kernel panic. The corresponding del_timer is also added in the
error path.

Reported-by: default avatarSami Liedes <sliedes@cc.hut.fi>
Signed-off-by: default avatarTao Ma <boyu.mt@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 6cba611e

fs/ext4/super.c

+5 −3
Original line number Diff line number Diff line
@@ -3391,6 +3391,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	get_random_bytes(&sbi->s_next_generation, sizeof(u32));

	spin_lock_init(&sbi->s_next_gen_lock);



	init_timer(&sbi->s_err_report);

	sbi->s_err_report.function = print_daily_error_info;

	sbi->s_err_report.data = (unsigned long) sb;



	err = percpu_counter_init(&sbi->s_freeblocks_counter,

			ext4_count_free_blocks(sb));

	if (!err) {
@@ -3652,9 +3656,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,

		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);



	init_timer(&sbi->s_err_report);

	sbi->s_err_report.function = print_daily_error_info;

	sbi->s_err_report.data = (unsigned long) sb;

	if (es->s_error_count)

		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
@@ -3678,6 +3679,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		sbi->s_journal = NULL;

	}

failed_mount3:

	del_timer(&sbi->s_err_report);

	if (sbi->s_flex_groups) {

		if (is_vmalloc_addr(sbi->s_flex_groups))

			vfree(sbi->s_flex_groups);