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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-25 03:39:30 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-25 03:39:30 +0300 |
| commit | 8be3a53e18e0e1a98f288f6c7f5e9da3adbe9c49 (patch) | |
| tree | ca6712858c68b3670e21132e90eb5b425c4039c6 /fs | |
| parent | fc10807db5ced090d83cec167e87c95a47452d24 (diff) | |
| parent | 3c597282887fd55181578996dca52ce697d985a5 (diff) | |
| download | linux-8be3a53e18e0e1a98f288f6c7f5e9da3adbe9c49.tar.xz | |
Merge tag 'erofs-for-5.8-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs fix from Gao Xiang:
"Fix a regression which uses potential uninitialized high 32-bit value
unexpectedly recently observed with specific compiler options"
* tag 'erofs-for-5.8-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: fix partially uninitialized misuse in z_erofs_onlinepage_fixup
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/erofs/zdata.h | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h index 7824f5563a55..9b66c28b3ae9 100644 --- a/fs/erofs/zdata.h +++ b/fs/erofs/zdata.h @@ -144,22 +144,22 @@ static inline void z_erofs_onlinepage_init(struct page *page) static inline void z_erofs_onlinepage_fixup(struct page *page, uintptr_t index, bool down) { - unsigned long *p, o, v, id; -repeat: - p = &page_private(page); - o = READ_ONCE(*p); + union z_erofs_onlinepage_converter u = { .v = &page_private(page) }; + int orig, orig_index, val; - id = o >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT; - if (id) { +repeat: + orig = atomic_read(u.o); + orig_index = orig >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT; + if (orig_index) { if (!index) return; - DBG_BUGON(id != index); + DBG_BUGON(orig_index != index); } - v = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) | - ((o & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down); - if (cmpxchg(p, o, v) != o) + val = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) | + ((orig & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down); + if (atomic_cmpxchg(u.o, orig, val) != orig) goto repeat; } |