| Message ID | 69333a8c-a5a7-5c76-bc39-8835f11b8dcf@omp.ru (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | nfs: fix undefined behavior in nfs_block_bits() | expand |
On 10 May 2024, at 16:24, Sergey Shtylyov wrote: > Shifting *signed int* typed constant 1 left by 31 bits causes undefined > behavior. Specify the correct *unsigned long* type by using 1UL instead. > > Found by Linux Verification Center (linuxtesting.org) with the Svace static > analysis tool. > > Cc: stable@vger.kernel.org > Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Ben
Index: linux-nfs/fs/nfs/internal.h =================================================================== --- linux-nfs.orig/fs/nfs/internal.h +++ linux-nfs/fs/nfs/internal.h @@ -710,9 +710,9 @@ unsigned long nfs_block_bits(unsigned lo if ((bsize & (bsize - 1)) || nrbitsp) { unsigned char nrbits; - for (nrbits = 31; nrbits && !(bsize & (1 << nrbits)); nrbits--) + for (nrbits = 31; nrbits && !(bsize & (1UL << nrbits)); nrbits--) ; - bsize = 1 << nrbits; + bsize = 1UL << nrbits; if (nrbitsp) *nrbitsp = nrbits; }
Shifting *signed int* typed constant 1 left by 31 bits causes undefined behavior. Specify the correct *unsigned long* type by using 1UL instead. Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Cc: stable@vger.kernel.org Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> --- This patch is against the master branch of Trond Myklebust's linux-nfs.git repo. fs/nfs/internal.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)