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authorAndy Adamson <andros@citi.umich.edu>2006-03-20 13:44:26 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-03-20 13:44:26 -0500
commit8dc7c3115b611c00006eac3ee5b108296432aab7 (patch)
treebe44c59907cbdcb6fdf46d0ad9cc140af757acfc /fs/nfs
parent2e0af86f618c697b44e2d67dff151256c58201c4 (diff)
locks,lockd: fix race in nlmsvc_testlock
posix_test_lock() returns a pointer to a struct file_lock which is unprotected and can be removed while in use by the caller. Move the conflicting lock from the return to a parameter, and copy the conflicting lock. In most cases the caller ends up putting the copy of the conflicting lock on the stack. On i386, sizeof(struct file_lock) appears to be about 100 bytes. We're assuming that's reasonable. Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/file.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 1cf07e4ad13..ee140c53dba 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -392,15 +392,14 @@ out_swapfile:
static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
{
- struct file_lock *cfl;
+ struct file_lock cfl;
struct inode *inode = filp->f_mapping->host;
int status = 0;
lock_kernel();
/* Try local locking first */
- cfl = posix_test_lock(filp, fl);
- if (cfl != NULL) {
- locks_copy_lock(fl, cfl);
+ if (posix_test_lock(filp, fl, &cfl)) {
+ locks_copy_lock(fl, &cfl);
goto out;
}