diff options
| author | Andrew Morton <akpm@linux-foundation.org> | 2007-06-03 13:50:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-04 13:25:10 -0700 |
| commit | 78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108 (patch) | |
| tree | ba550d1d94a11b8f758f905e40c3d2aa7494007d | |
| parent | 4c738480d21a190e3d99c7ce985ab9484f373a3c (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>
| -rw-r--r-- | fs/ioctl.c | 14 |
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 @@ #include <linux/fs.h> #include <linux/security.h> #include <linux/module.h> +#include <linux/kallsyms.h> #include <asm/uaccess.h> #include <asm/ioctls.h> @@ -20,6 +21,7 @@ static long do_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { int error = -ENOTTY; + void *f; if (!filp->f_op) goto out; @@ -29,10 +31,16 @@ static long do_ioctl(struct file *filp, unsigned int cmd, if (error == -ENOIOCTLCMD) error = -EINVAL; goto out; - } else if (filp->f_op->ioctl) { + } else if ((f = filp->f_op->ioctl)) { lock_kernel(); - error = filp->f_op->ioctl(filp->f_path.dentry->d_inode, - filp, cmd, arg); + if (!filp->f_op->ioctl) { + printk("%s: ioctl %p disappeared\n", __FUNCTION__, f); + print_symbol("symbol: %s\n", (unsigned long)f); + dump_stack(); + } else { + error = filp->f_op->ioctl(filp->f_path.dentry->d_inode, + filp, cmd, arg); + } unlock_kernel(); } |