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| author | Andy Adamson <andros@citi.umich.edu> | 2006-03-20 13:44:26 -0500 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2006-03-20 13:44:26 -0500 |
| commit | 8dc7c3115b611c00006eac3ee5b108296432aab7 (patch) | |
| tree | be44c59907cbdcb6fdf46d0ad9cc140af757acfc /fs/lockd | |
| parent | 2e0af86f618c697b44e2d67dff151256c58201c4 (diff) | |
| download | linux-8dc7c3115b611c00006eac3ee5b108296432aab7.tar.gz linux-8dc7c3115b611c00006eac3ee5b108296432aab7.tar.bz2 linux-8dc7c3115b611c00006eac3ee5b108296432aab7.zip | |
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/lockd')
| -rw-r--r-- | fs/lockd/svclock.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index f5398097b84b..d683dd022e08 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -376,8 +376,6 @@ u32 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, struct nlm_lock *conflock) { - struct file_lock *fl; - dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", file->f_file->f_dentry->d_inode->i_sb->s_id, file->f_file->f_dentry->d_inode->i_ino, @@ -385,14 +383,14 @@ nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, (long long)lock->fl.fl_start, (long long)lock->fl.fl_end); - if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) { + if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", - fl->fl_type, (long long)fl->fl_start, - (long long)fl->fl_end); + conflock->fl.fl_type, + (long long)conflock->fl.fl_start, + (long long)conflock->fl.fl_end); conflock->caller = "somehost"; /* FIXME */ conflock->oh.len = 0; /* don't return OH info */ - conflock->svid = fl->fl_pid; - conflock->fl = *fl; + conflock->svid = conflock->fl.fl_pid; return nlm_lck_denied; } |