From 3c0a2e0b0ae661457c8505fecc7be5501aa7a715 Mon Sep 17 00:00:00 2001 From: Sergey Shtylyov Date: Fri, 10 May 2024 23:24:04 +0300 Subject: [PATCH] nfs: fix undefined behavior in nfs_block_bits() 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 Reviewed-by: Benjamin Coddington Signed-off-by: Trond Myklebust --- fs/nfs/internal.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index dc0693b3d214..9f0f4534744b 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -717,9 +717,9 @@ unsigned long nfs_block_bits(unsigned long bsize, unsigned char *nrbitsp) 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; }