From 8dc7c3115b611c00006eac3ee5b108296432aab7 Mon Sep 17 00:00:00 2001 From: Andy Adamson Date: Mon, 20 Mar 2006 13:44:26 -0500 Subject: 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 Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'fs/nfs') 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; } -- cgit v1.2.2