On Tue, Sep 12, 2023 at 04:36:55PM -0700, Randy Dunlap wrote:
>
>
> On 9/11/23 22:26, Stephen Rothwell wrote:
> > Hi all,
> >
> > Changes since 20230911:
> >
> > New tree: bcachefs
> >
> > The bcachefs tree gained a semantic conflict against Linus' tree for
> > which I applied a patch.
> >
> > The wireless-next tree gaind a conflict against the wireless tree.
> >
> > Non-merge commits (relative to Linus' tree): 4095
> > 1552 files changed, 346893 insertions(+), 22945 deletions(-)
> >
> > ----------------------------------------------------------------------------
>
> on x86_64:
>
> vmlinux.o: warning: objtool: bch2_dev_buckets_reserved.part.0() is missing an ELF size annotation
Here ya go:
---8<---
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Subject: [PATCH] bcachefs: Remove undefined behavior in bch2_dev_buckets_reserved()
In general it's a good idea to avoid using bare unreachable() because it
introduces undefined behavior in compiled code. In this case it even
confuses GCC into emitting an empty unused
bch2_dev_buckets_reserved.part.0() function.
Use BUG() instead, which is nice and defined. While in theory it should
never trigger, if something were to go awry and the BCH_WATERMARK_NR
case were to actually hit, the failure mode is much more robust.
Fixes the following warnings:
vmlinux.o: warning: objtool: bch2_bucket_alloc_trans() falls through to next function bch2_reset_alloc_cursors()
vmlinux.o: warning: objtool: bch2_dev_buckets_reserved.part.0() is missing an ELF size annotation
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
fs/bcachefs/buckets.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/bcachefs/buckets.h b/fs/bcachefs/buckets.h
index f192809f50cf..0eff05c79c65 100644
--- a/fs/bcachefs/buckets.h
+++ b/fs/bcachefs/buckets.h
@@ -180,7 +180,7 @@ static inline u64 bch2_dev_buckets_reserved(struct bch_dev *ca, enum bch_waterma
switch (watermark) {
case BCH_WATERMARK_NR:
- unreachable();
+ BUG();
case BCH_WATERMARK_stripe:
reserved += ca->mi.nbuckets >> 6;
fallthrough;
--
2.41.0
