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| author | Jaeyeon Lee <jaeyeon.lee.dev@gmail.com> | 2026-07-08 13:19:41 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-04 19:18:35 -0700 |
| commit | 889d3783ae3f78c8593bc7837a2a68b49db4166d (patch) | |
| tree | 4147cdd58468c1e0ebdfb1546f447b752fd340c3 /mm/shmem.c | |
| parent | 3fe0620fae7c2a14e9aaad251c6eb225b6c16dc0 (diff) | |
| download | linux-next-889d3783ae3f78c8593bc7837a2a68b49db4166d.tar.gz linux-next-889d3783ae3f78c8593bc7837a2a68b49db4166d.zip | |
mm/shmem: annotate benign data-race in shmem_getattr()
shmem_getattr() reads info->alloced, info->swapped and i_mapping->nrpages
without info->lock to decide whether shmem_recalc_inode() should be
called. shmem_recalc_inode() recomputes these under info->lock, so a
stale read here only affects whether shmem_recalc_inode() runs.
Annotate data_race() to silence KCSAN.
Link: https://lore.kernel.org/20260708111941.35460-1-jaeyeon.lee.dev@gmail.com
Signed-off-by: Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>
Reported-by: syzbot+dfb578404df369f6599b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=dfb578404df369f6599b
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index fa8bb59f87b4..0a36b48f667e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1297,7 +1297,8 @@ static int shmem_getattr(struct mnt_idmap *idmap, struct inode *inode = path->dentry->d_inode; struct shmem_inode_info *info = SHMEM_I(inode); - if (info->alloced - info->swapped != inode->i_mapping->nrpages) + /* Fast-path hint; recalc under info->lock corrects any stale read. */ + if (data_race(info->alloced - info->swapped != inode->i_mapping->nrpages)) shmem_recalc_inode(inode, 0, 0); if (info->fsflags & FS_APPEND_FL) |