From afb28ca1f1ebe5279ffedd2fb24b92b8ee968351 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Fri, 23 Oct 2026 14:25:02 -0700 Subject: [PATCH] ext2: Make sbi an proper alias for EXT2_SB(sb) in ext2_fill_super() A recent LLVM change to fix parsing and validating __guarded_by on structure members [1] reveals a couple of warnings in ext2_fill_super() from the annotations added by commit 023051c2d0f1 ("ext2: mark s_mount_state as guarded by s_lock") and commit c23746524faf ("ext2: annotate s_rsv_window_root as requiring s_rsv_window_lock"): fs/ext2/super.c:1040:7: error: writing variable 's_mount_state' requires holding spinlock '_res->s_lock' exclusively [-Werror,-Wthread-safety-precise] 1040 | sbi->s_mount_state = le16_to_cpu(es->s_state); | ^ fs/ext2/super.c:1040:7: note: found near match 'EXT2_SB(sb).s_lock' fs/ext2/super.c:1138:8: error: writing variable 's_rsv_window_root' requires holding spinlock '_res->s_rsv_window_lock' exclusively [-Werror,-Wthread-safety-precise] 1138 | sbi->s_rsv_window_root = RB_ROOT; | ^ fs/ext2/super.c:1138:8: note: found near match 'EXT2_SB(sb).s_rsv_window_lock' Context analysis does very minimal alias detection [2], so it is not able to figure out that sbi == sb->s_fs_info == EXT2_SB(sb). The only reason there were no warnings before the above LLVM change is because the annotation was not parsed and verified correctly. Rework the allocation and assignment of sbi to have a direct assignment of EXT2_SB(sb) to sbi so that the analysis knows that sbi and EXT2_SB(sb) refer to the same object, clearing up the warnings. Fixes: 9708538ba204 ("ext2: enable context analysis support for ext2 filesystem") Link: https://github.com/llvm/llvm-project/commit/217e229a1f32785fccdd3b3f51429f0d309dea45 [1] Link: https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#no-alias-analysis [2] Signed-off-by: Nathan Chancellor Reviewed-by: Marco Elver Link: https://patch.msgid.link/20261023-ext2-fix-context-analysis-clang-24-v2-1-a33961453899@kernel.org Signed-off-by: Jan Kara --- fs/ext2/super.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index fb217ef2d69f..bde5b433776c 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -883,17 +883,18 @@ static int ext2_fill_super(struct super_block *sb, struct fs_context *fc) __le32 features; int err; - sbi = kzalloc_obj(*sbi); - if (!sbi) + sb->s_fs_info = kzalloc_obj(*sbi); + if (!sb->s_fs_info) return -ENOMEM; + sbi = EXT2_SB(sb); sbi->s_blockgroup_lock = kzalloc_obj(struct blockgroup_lock); if (!sbi->s_blockgroup_lock) { - kfree(sbi); + kfree(sb->s_fs_info); + sb->s_fs_info = NULL; return -ENOMEM; } - sb->s_fs_info = sbi; sbi->s_sb_block = sb_block; guard(spinlock_init)(&EXT2_SB(sb)->s_lock);