From 50e1f8d22199b557337b3d1ec8520e4c5aa5c76e Mon Sep 17 00:00:00 2001
From: Chao Yu <chao2.yu@samsung.com>
Date: Mon, 7 Jul 2014 09:39:32 +0800
Subject: [PATCH] f2fs: avoid to access NULL pointer in issue_flush_thread
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=75861
Denis 2014-05-10 11:28:59 UTC reported:
"F2FS-fs (mmcblk0p28): mounting..
Unable to handle kernel NULL pointer dereference at virtual address 00000018
...
[<c0a2f678>] (_raw_spin_lock+0x3c/0x70) from [<c03a0330>] (issue_flush_thread+0x50/0x17c)
[<c03a0330>] (issue_flush_thread+0x50/0x17c) from [<c01b4064>] (kthread+0x98/0xa4)
[<c01b4064>] (kthread+0x98/0xa4) from [<c0108060>] (kernel_thread_exit+0x0/0x8)"
This patch assign cmd_control_info in sm_info before issue_flush_thread is being
created, so this make sure that issue flush thread will have no chance to access
invalid info in fcc.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/segment.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index b22d5a0652bb0b..d04613df710a7e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -272,14 +272,15 @@ int create_flush_cmd_control(struct f2fs_sb_info *sbi)
return -ENOMEM;
spin_lock_init(&fcc->issue_lock);
init_waitqueue_head(&fcc->flush_wait_queue);
+ sbi->sm_info->cmd_control_info = fcc;
fcc->f2fs_issue_flush = kthread_run(issue_flush_thread, sbi,
"f2fs_flush-%u:%u", MAJOR(dev), MINOR(dev));
if (IS_ERR(fcc->f2fs_issue_flush)) {
err = PTR_ERR(fcc->f2fs_issue_flush);
kfree(fcc);
+ sbi->sm_info->cmd_control_info = NULL;
return err;
}
- sbi->sm_info->cmd_control_info = fcc;
return err;
}
--
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