Linus Torvalds wrote:
>
> On Sat, 5 May 2001, Manfred Spraul wrote:
> >
> > * missing/wrong lock_kernel calls in fs/fcntl.c: getlk/setlk run without
> > the big kernel lock. The ..64 function acquire the lock.
>
> This is wrong. The big lock (if it is needed, but I thought the current
> locking should be safe) should be pushed down into the point where it is
> needed, not at the caller..
>
Ok, I've removed the locks from fs/fcntl.c and added them into
fs/locks.c:
* fcntl_getlease dereferences filp->f_dentry->d_inode->i_flock. Race
with multithreaded app: sys_close()->filp_close()->locks_remove_posix()
+ fcntl_getlease()
* according to Documentation/filesystems/Locking, f_op->lock() is called
with the blk acquired. lock added around that call in
fcntl_{get,set}lk{,64}
I've attached a new patch.
-- Manfred
// $Header$ // Kernel Version: // VERSION = 2 // PATCHLEVEL = 4 // SUBLEVEL = 4 // EXTRAVERSION = --- 2.4/fs/fcntl.c Thu Nov 16 07:50:25 2000 +++ build-2.4/fs/fcntl.c Sat May 5 00:32:17 2001 @@ -338,7 +338,6 @@ if (!filp) goto out; - lock_kernel(); switch (cmd) { case F_GETLK64: err = fcntl_getlk64(fd, (struct flock64 *) arg); @@ -353,7 +352,6 @@ err = do_fcntl(fd, cmd, arg, filp); break; } - unlock_kernel(); fput(filp); out: return err; --- 2.4/fs/locks.c Sun Apr 22 13:21:33 2001 +++ build-2.4/fs/locks.c Sat May 5 01:20:50 2001 @@ -1157,11 +1157,16 @@ int fcntl_getlease(struct file *filp) { struct file_lock *fl; - + int ret; + + lock_kernel(); fl = filp->f_dentry->d_inode->i_flock; if ((fl == NULL) || ((fl->fl_flags & FL_LEASE) == 0)) - return F_UNLCK; - return fl->fl_type & ~F_INPROGRESS; + ret = F_UNLCK; + else + fl->fl_type & ~F_INPROGRESS; + unlock_kernel(); + return ret; } /* We already had a lease on this file; just change its type */ @@ -1357,7 +1362,9 @@ goto out_putf; if (filp->f_op && filp->f_op->lock) { + lock_kernel(); error = filp->f_op->lock(filp, F_GETLK, &file_lock); + unlock_kernel(); if (error < 0) goto out_putf; else if (error == LOCK_USE_CLNT) @@ -1481,7 +1488,9 @@ } if (filp->f_op && filp->f_op->lock != NULL) { + lock_kernel(); error = filp->f_op->lock(filp, cmd, file_lock); + unlock_kernel(); if (error < 0) goto out_putf; } @@ -1522,7 +1531,9 @@ goto out_putf; if (filp->f_op && filp->f_op->lock) { + lock_kernel(); error = filp->f_op->lock(filp, F_GETLK, &file_lock); + unlock_kernel(); if (error < 0) goto out_putf; else if (error == LOCK_USE_CLNT) @@ -1619,7 +1630,9 @@ } if (filp->f_op && filp->f_op->lock != NULL) { + lock_kernel(); error = filp->f_op->lock(filp, cmd, file_lock); + unlock_kernel(); if (error < 0) goto out_putf; }
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This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:21 EST