* [PATCH] nfsd: avoid undefined signed overflow
@ 2013-05-17 20:16 Jim Rees
0 siblings, 0 replies; only message in thread
From: Jim Rees @ 2013-05-17 20:16 UTC (permalink / raw)
To: Bruce Fields; +Cc: linux-nfs
In C, signed integer overflow results in undefined behavior, but unsigned
overflow wraps around. So do the subtraction first, then cast to signed.
Signed-off-by: Jim Rees <rees@umich.edu>
---
fs/nfsd/nfs4state.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 316ec84..9850329 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3427,7 +3427,7 @@ grace_disallows_io(struct net *net, struct inode *inode)
/* Returns true iff a is later than b: */
static bool stateid_generation_after(stateid_t *a, stateid_t *b)
{
- return (s32)a->si_generation - (s32)b->si_generation > 0;
+ return (s32)(a->si_generation - b->si_generation) > 0;
}
static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_session)
--
1.8.2.3
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