aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ioctl.c
diff options
context:
space:
mode:
authorAndrew Morton <akpm@linux-foundation.org>2007-06-03 16:50:41 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-04 16:25:10 -0400
commit78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108 (patch)
treeba550d1d94a11b8f758f905e40c3d2aa7494007d /fs/ioctl.c
parent4c738480d21a190e3d99c7ce985ab9484f373a3c (diff)
vanishing ioctl handler debugging
We've had several reoprts of the CPU jumping to 0x00000000 is do_ioctl(). I assume that there's a race and someone is zeroing out the ioctl handler while this CPU waits for the lock_kernel(). The patch adds code to detect this, then emits stuff which will hopefuly lead us to the culprit. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ioctl.c')
-rw-r--r--fs/ioctl.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 479c1038ed4a..8c90cbc903fa 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -12,6 +12,7 @@
12#include <linux/fs.h> 12#include <linux/fs.h>
13#include <linux/security.h> 13#include <linux/security.h>
14#include <linux/module.h> 14#include <linux/module.h>
15#include <linux/kallsyms.h>
15 16
16#include <asm/uaccess.h> 17#include <asm/uaccess.h>
17#include <asm/ioctls.h> 18#include <asm/ioctls.h>
@@ -20,6 +21,7 @@ static long do_ioctl(struct file *filp, unsigned int cmd,
20 unsigned long arg) 21 unsigned long arg)
21{ 22{
22 int error = -ENOTTY; 23 int error = -ENOTTY;
24 void *f;
23 25
24 if (!filp->f_op) 26 if (!filp->f_op)
25 goto out; 27 goto out;
@@ -29,10 +31,16 @@ static long do_ioctl(struct file *filp, unsigned int cmd,
29 if (error == -ENOIOCTLCMD) 31 if (error == -ENOIOCTLCMD)
30 error = -EINVAL; 32 error = -EINVAL;
31 goto out; 33 goto out;
32 } else if (filp->f_op->ioctl) { 34 } else if ((f = filp->f_op->ioctl)) {
33 lock_kernel(); 35 lock_kernel();
34 error = filp->f_op->ioctl(filp->f_path.dentry->d_inode, 36 if (!filp->f_op->ioctl) {
35 filp, cmd, arg); 37 printk("%s: ioctl %p disappeared\n", __FUNCTION__, f);
38 print_symbol("symbol: %s\n", (unsigned long)f);
39 dump_stack();
40 } else {
41 error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
42 filp, cmd, arg);
43 }
36 unlock_kernel(); 44 unlock_kernel();
37 } 45 }
38 46