Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108
Commit: 78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108
Parent: 4c738480d21a190e3d99c7ce985ab9484f373a3c
Author: Andrew Morton <[EMAIL PROTECTED]>
AuthorDate: Sun Jun 3 13:50:41 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Jun 4 13:25:10 2007 -0700
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 <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/ioctl.c | 14 +++++++++++---
1 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 479c103..8c90cbc 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();
}
-
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