From: David Howells <dhowells@redhat.com>
To: linux-afs@lists.infradead.org
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
Dan Carpenter <dan.carpenter@oracle.com>,
dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 02/11] afs: Fix tracing deref-before-check
Date: Wed, 28 Oct 2020 14:10:02 +0000 [thread overview]
Message-ID: <160389420288.300137.3760370136797987174.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <160389418807.300137.8222864749005731859.stgit@warthog.procyon.org.uk>
The patch dca54a7bbb8c: "afs: Add tracing for cell refcount and active user
count" from Oct 13, 2020, leads to the following Smatch complaint:
fs/afs/cell.c:596 afs_unuse_cell()
warn: variable dereferenced before check 'cell' (see line 592)
Fix this by moving the retrieval of the cell debug ID to after the check of
the validity of the cell pointer.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: dca54a7bbb8c ("afs: Add tracing for cell refcount and active user count")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Dan Carpenter <dan.carpenter@oracle.com>
---
fs/afs/cell.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 52233fa6195f..887b673f6223 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -589,7 +589,7 @@ struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)
*/
void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_trace reason)
{
- unsigned int debug_id = cell->debug_id;
+ unsigned int debug_id;
time64_t now, expire_delay;
int u, a;
@@ -604,6 +604,7 @@ void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_tr
if (cell->vl_servers->nr_servers)
expire_delay = afs_cell_gc_delay;
+ debug_id = cell->debug_id;
u = atomic_read(&cell->ref);
a = atomic_dec_return(&cell->active);
trace_afs_cell(debug_id, u, a, reason);
next prev parent reply other threads:[~2020-10-28 22:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-28 14:09 [PATCH 00/11] AFS fixes [ver #2] David Howells
2020-10-28 14:09 ` [PATCH 01/11] afs: Fix copy_file_range() David Howells
2020-10-28 14:10 ` David Howells [this message]
2020-10-28 14:10 ` [PATCH 03/11] afs: Fix a use after free in afs_xattr_get_acl() David Howells
2020-10-28 14:10 ` [PATCH 04/11] afs: Fix afs_launder_page to not clear PG_writeback David Howells
2020-10-28 14:10 ` [PATCH 05/11] afs: Fix to take ref on page when PG_private is set David Howells
2020-10-28 14:20 ` Matthew Wilcox
2020-10-28 15:24 ` David Howells
2020-10-28 14:10 ` [PATCH 06/11] afs: Fix page leak on afs_write_begin() failure David Howells
2020-10-28 14:10 ` [PATCH 07/11] afs: Fix where page->private is set during write David Howells
2020-10-28 14:10 ` [PATCH 08/11] afs: Wrap page->private manipulations in inline functions David Howells
2020-10-28 14:10 ` [PATCH 09/11] afs: Alter dirty range encoding in page->private David Howells
2020-10-28 14:10 ` [PATCH 10/11] afs: Fix afs_invalidatepage to adjust the dirty region David Howells
2020-10-28 14:11 ` [PATCH 11/11] afs: Fix dirty-region encoding on ppc32 with 64K pages David Howells
2020-10-28 14:34 ` Matthew Wilcox
2020-10-28 16:53 ` David Howells
2020-10-28 17:05 ` David Howells
2020-10-28 17:11 ` Matthew Wilcox
2020-10-28 17:27 ` David Howells
2020-10-28 22:22 [PATCH 00/11] AFS fixes [ver #3] David Howells
2020-10-28 22:22 ` [PATCH 02/11] afs: Fix tracing deref-before-check David Howells
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