From ae0027869db7d28563cd783865fab04ffd18419c Mon Sep 17 00:00:00 2001 From: Hiroshi Shimamoto Date: Thu, 14 Feb 2008 10:26:24 -0800 Subject: [PATCH] latencytop: fix kernel panic while reading latency proc file Reading /proc//latency or /proc//task//latency could cause NULL pointer dereference. In lstats_open(), get_proc_task() can return NULL, in which case the kernel will oops at lstats_show_proc() because m->private is NULL. When get_proc_task() returns NULL, the kernel should return -ENOENT. This can be reproduced by the following script. while : do date bash -c 'ls > ls.$$' & pid=$! cat /proc/$pid/latency & cat /proc/$pid/latency & cat /proc/$pid/latency & cat /proc/$pid/latency done Signed-off-by: Hiroshi Shimamoto Signed-off-by: Ingo Molnar --- fs/proc/base.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/proc/base.c b/fs/proc/base.c index 96ee899d6502..989e3078d7af 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -350,6 +350,8 @@ static int lstats_open(struct inode *inode, struct file *file) struct seq_file *m; struct task_struct *task = get_proc_task(inode); + if (!task) + return -ENOENT; ret = single_open(file, lstats_show_proc, NULL); if (!ret) { m = file->private_data; -- 2.30.2