diff options
| author | Mike Snitzer <snitzer@kernel.org> | 2025-11-26 01:01:25 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-11 15:26:20 +0100 |
| commit | 7a28d65e4beb7627738b75c6a23f36ae54470f93 (patch) | |
| tree | 633c723312e3a68710b59c9d6956ebd6d1ac2f3d | |
| parent | 98a26893fad4180d8ea210d8749392790dfddc81 (diff) | |
nfs/localio: fix regression due to out-of-order __put_cred
commit 3af870aedbff10bfed220e280b57a405e972229f upstream.
Commit f2060bdc21d7 ("nfs/localio: add refcounting for each iocb IO
associated with NFS pgio header") inadvertantly reintroduced the same
potential for __put_cred() triggering BUG_ON(cred == current->cred) that
commit 992203a1fba5 ("nfs/localio: restore creds before releasing pageio
data") fixed.
Fix this by saving and restoring the cred around each {read,write}_iter
call within the respective for loop of nfs_local_call_{read,write} using
scoped_with_creds().
NOTE: this fix started by first reverting the following commits:
94afb627dfc2 ("nfs: use credential guards in nfs_local_call_read()")
bff3c841f7bd ("nfs: use credential guards in nfs_local_call_write()")
1d18101a644e ("Merge tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs")
followed by narrowly fixing the cred lifetime issue by using
scoped_with_creds(). In doing so, this commit's changes appear more
extensive than they really are (as evidenced by comparing to v6.18's
fs/nfs/localio.c).
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Acked-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/linux-next/20251205111942.4150b06f@canb.auug.org.au/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/nfs/localio.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index b98bb292fef0..ed2a7efaf8f2 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -623,8 +623,6 @@ static void nfs_local_call_read(struct work_struct *work) ssize_t status; int n_iters; - save_cred = override_creds(filp->f_cred); - n_iters = atomic_read(&iocb->n_iters); for (int i = 0; i < n_iters ; i++) { if (iocb->iter_is_dio_aligned[i]) { @@ -637,7 +635,10 @@ static void nfs_local_call_read(struct work_struct *work) } else iocb->kiocb.ki_flags &= ~IOCB_DIRECT; + save_cred = override_creds(filp->f_cred); status = filp->f_op->read_iter(&iocb->kiocb, &iocb->iters[i]); + revert_creds(save_cred); + if (status != -EIOCBQUEUED) { if (unlikely(status >= 0 && status < iocb->iters[i].count)) force_done = true; /* Partial read */ @@ -647,8 +648,6 @@ static void nfs_local_call_read(struct work_struct *work) } } } - - revert_creds(save_cred); } static int @@ -830,7 +829,6 @@ static void nfs_local_call_write(struct work_struct *work) int n_iters; current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; - save_cred = override_creds(filp->f_cred); file_start_write(filp); n_iters = atomic_read(&iocb->n_iters); @@ -845,7 +843,10 @@ static void nfs_local_call_write(struct work_struct *work) } else iocb->kiocb.ki_flags &= ~IOCB_DIRECT; + save_cred = override_creds(filp->f_cred); status = filp->f_op->write_iter(&iocb->kiocb, &iocb->iters[i]); + revert_creds(save_cred); + if (status != -EIOCBQUEUED) { if (unlikely(status >= 0 && status < iocb->iters[i].count)) force_done = true; /* Partial write */ @@ -857,7 +858,6 @@ static void nfs_local_call_write(struct work_struct *work) } file_end_write(filp); - revert_creds(save_cred); current->flags = old_flags; } |