Messages in this thread Patch in this message | | | Date | Fri, 03 Apr 2009 15:31:34 +0800 | From | Li Zefan <> | Subject | [PATCH] blktrace: fix a bug in blk_msg_write() |
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This is another long-standing bug.
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(console 1) # echo -n 'a' > /sys/kernel/debug/block/sda/msg (console 2) # blktrace -d /dev/sda -a pc -o - | blkparse -i - 8,0 0 0 0.000000000 0 m N a������@��
We should terminate the msg buffer with '\0'.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> --- kernel/trace/blktrace.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index c0ef70d..2bf341f 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -327,10 +327,10 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, char *msg; struct blk_trace *bt; - if (count > BLK_TN_MAX_MSG) + if (count >= BLK_TN_MAX_MSG) return -EINVAL; - msg = kmalloc(count, GFP_KERNEL); + msg = kmalloc(count + 1, GFP_KERNEL); if (msg == NULL) return -ENOMEM; @@ -338,6 +338,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, kfree(msg); return -EFAULT; } + msg[count] = '\0'; bt = filp->private_data; __trace_note_message(bt, "%s", msg); -- 1.5.4.rc3
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