On 01/05/2013 01:19 PM, Nickolai Zeldovich wrote: > Shifting a 32-bit int by 32 bits is undefined behavior in C, and > results in different behavior on different architectures (e.g., x86 > and PowerPC). diAlloc() in fs/jfs/jfs_imap.c computes a mask using > 0xffffffffu<<(32-bitno), which can left-shift by 32 bits. To avoid > unexpected behavior, explicitly check for bitno==0 and use a 0 mask.
Thanks. Pushed to git://github.com/kleikamp/linux-shaggy.git jfs-next Shaggy > > Signed-off-by: Nickolai Zeldovich <nicko...@csail.mit.edu> > --- > fs/jfs/jfs_imap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c > index 6ba4006..f7e042b 100644 > --- a/fs/jfs/jfs_imap.c > +++ b/fs/jfs/jfs_imap.c > @@ -1493,7 +1493,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode > *ip) > /* mask any prior bits for the starting words of the > * summary map. > */ > - mask = ONES << (EXTSPERSUM - bitno); > + mask = (bitno == 0) ? 0 : (ONES << (EXTSPERSUM - bitno)); > inosmap = le32_to_cpu(iagp->inosmap[sword]) | mask; > extsmap = le32_to_cpu(iagp->extsmap[sword]) | mask; > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
