From: Arnd Bergmann Date: Fri, 15 May 2026 20:44:46 +0000 (+0200) Subject: fat: avoid stack overflow warning X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e1a1729419e3e440668dbc1ae95b0dc2004172fe;p=thirdparty%2Flinux.git fat: avoid stack overflow warning Building the fat kunit tests on with -fsanitize=alignment reveals some rather excessive stack usage: fs/fat/fat_test.c: In function 'fat_clus_to_blknr_test': fs/fat/fat_test.c:33:1: error: the frame size of 4736 bytes is larger than 1536 bytes [-Werror=frame-larger-than=] 33 | } | ^ fs/fat/fat_test.c: In function 'fat_get_blknr_offset_test': fs/fat/fat_test.c:52:1: error: the frame size of 4800 bytes is larger than 1536 bytes [-Werror=frame-larger-than=] The problem is clearly related to the on-stack copy of a local msdos_sb_info structure. Avoid this by making that copy 'static const' and changing the called functions to accept a constant input. Link: https://lore.kernel.org/20260515204456.2692208-1-arnd@kernel.org Fixes: 410002f8139c ("kunit: fat: test cluster and directory i_pos layout helpers") Signed-off-by: Arnd Bergmann Acked-by: OGAWA Hirofumi Cc: Christian Brauner Cc: Jan Kara Cc: Adi Nata Cc: David Laight Signed-off-by: Andrew Morton --- diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 99ed9228a677..2772675bd35a 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -249,13 +249,13 @@ static inline unsigned char fat_checksum(const __u8 *name) return s; } -static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus) +static inline sector_t fat_clus_to_blknr(const struct msdos_sb_info *sbi, int clus) { return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus + sbi->data_start; } -static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi, +static inline void fat_get_blknr_offset(const struct msdos_sb_info *sbi, loff_t i_pos, sector_t *blknr, int *offset) { *blknr = i_pos >> sbi->dir_per_block_bits; diff --git a/fs/fat/fat_test.c b/fs/fat/fat_test.c index 4eeed9dca549..9583ce66dca3 100644 --- a/fs/fat/fat_test.c +++ b/fs/fat/fat_test.c @@ -22,7 +22,7 @@ static void fat_checksum_test(struct kunit *test) static void fat_clus_to_blknr_test(struct kunit *test) { - struct msdos_sb_info sbi = { + static const struct msdos_sb_info sbi = { .sec_per_clus = 4, .data_start = 100, }; @@ -34,7 +34,7 @@ static void fat_clus_to_blknr_test(struct kunit *test) static void fat_get_blknr_offset_test(struct kunit *test) { - struct msdos_sb_info sbi = { + static const struct msdos_sb_info sbi = { .dir_per_block = 16, .dir_per_block_bits = 4, };