On Fri 01-11-24 14:45:23, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end was introduced in GCC-14, and we > are getting ready to enable it, globally. > > Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of > a flexible structure (`struct shash_desc`) where the size of the > flexible-array member (`__ctx`) is known at compile-time, and > refactor the rest of the code, accordingly. > > So, with this, fix 77 of the following warnings: > > include/linux/jbd2.h:1800:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > --- > Changes in v2: > - Use DIV_ROUND_UP() to compute the number of elements for the flex > array. (Jan Kara) > > v1: > - Link: https://lore.kernel.org/linux-hardening/ZxvyavDjXDaV9cNg@kspp/ > > include/linux/jbd2.h | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h > index 8aef9bb6ad57..50f7ea8714bf 100644 > --- a/include/linux/jbd2.h > +++ b/include/linux/jbd2.h > @@ -1796,22 +1796,21 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal) > static inline u32 jbd2_chksum(journal_t *journal, u32 crc, > const void *address, unsigned int length) > { > - struct { > - struct shash_desc shash; > - char ctx[JBD_MAX_CHECKSUM_SIZE]; > - } desc; > + DEFINE_RAW_FLEX(struct shash_desc, desc, __ctx, > + DIV_ROUND_UP(JBD_MAX_CHECKSUM_SIZE, > + sizeof(*((struct shash_desc *)0)->__ctx))); > int err; > > BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) > > JBD_MAX_CHECKSUM_SIZE); > > - desc.shash.tfm = journal->j_chksum_driver; > - *(u32 *)desc.ctx = crc; > + desc->tfm = journal->j_chksum_driver; > + *(u32 *)desc->__ctx = crc; > > - err = crypto_shash_update(&desc.shash, address, length); > + err = crypto_shash_update(desc, address, length); > BUG_ON(err); > > - return *(u32 *)desc.ctx; > + return *(u32 *)desc->__ctx; > } > > /* Return most recent uncommitted transaction */ > -- > 2.43.0 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
