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From: Gabriel de Perthuis <g2p.code@gmail.com>
To: Kent Overstreet <kent.overstreet@linux.dev>,
	linux-bcachefs@vger.kernel.org, Joshua Ashton <joshua@froggi.es>
Cc: "André Almeida" <andrealmeid@igalia.com>,
	"Gabriel Krisman Bertazi" <krisman@suse.de>,
	"Gabriel de Perthuis" <g2p.code@gmail.com>
Subject: [PATCH] bcachefs: Use flexible arrays in dirent
Date: Fri, 21 Feb 2025 18:26:27 +0000	[thread overview]
Message-ID: <f048a5a514b41af8523618ab759c3e79df130954.1740161242.git.g2p.code@gmail.com> (raw)
In-Reply-To: <20250213184607.18237-19-kent.overstreet@linux.dev>

A fake d_name[0]/d_names[0] flexible array tickled UBSAN.

Use DECLARE_FLEX_ARRAY to work around a compiler restriction on flex
arrays in unions:
https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Fixes: "bcachefs: bcachefs_metadata_version_casefolding"
Closes: https://github.com/koverstreet/bcachefs/issues/824

Signed-off-by: Gabriel de Perthuis <g2p.code@gmail.com>
---
 fs/bcachefs/dirent_format.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/bcachefs/dirent_format.h b/fs/bcachefs/dirent_format.h
index 2e766032e1e91..a46dbddd21aad 100644
--- a/fs/bcachefs/dirent_format.h
+++ b/fs/bcachefs/dirent_format.h
@@ -42,13 +42,13 @@ struct bch_dirent {
 	union {
 	struct {
 		__u8		d_pad;
 		__le16		d_name_len;
 		__le16		d_cf_name_len;
-		__u8		d_names[0];
+		__u8		d_names[];
 	} d_cf_name_block __packed;
-	__u8			d_name[0];
+	__DECLARE_FLEX_ARRAY(__u8, d_name);
 	} __packed;
 } __packed __aligned(8);
 
 #define DT_SUBVOL	16
 #define BCH_DT_MAX	17
-- 
2.45.2


  reply	other threads:[~2025-02-21 18:26 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-13 18:45 [PATCH 00/18] last on disk format changes before freeze Kent Overstreet
2025-02-13 18:45 ` [PATCH 01/18] bcachefs: bch2_lru_change() checks for no-op Kent Overstreet
2025-02-13 18:45 ` [PATCH 02/18] bcachefs: s/BCH_LRU_FRAGMENTATION_START/BCH_LRU_BUCKET_FRAGMENTATION/ Kent Overstreet
2025-02-13 18:45 ` [PATCH 03/18] bcachefs: decouple bch2_lru_check_set() from alloc btree Kent Overstreet
2025-02-13 18:45 ` [PATCH 04/18] bcachefs: Rework bch2_check_lru_key() Kent Overstreet
2025-02-13 18:45 ` [PATCH 05/18] bcachefs: bch2_trigger_stripe_ptr() no longer uses ec_stripes_heap_lock Kent Overstreet
2025-02-13 18:45 ` [PATCH 06/18] bcachefs: Better trigger ordering Kent Overstreet
2025-02-13 18:45 ` [PATCH 07/18] bcachefs: rework bch2_trans_commit_run_triggers() Kent Overstreet
2025-02-13 18:45 ` [PATCH 08/18] bcachefs: bcachefs_metadata_version_cached_backpointers Kent Overstreet
2025-02-13 18:45 ` [PATCH 09/18] bcachefs: Invalidate cached data by backpointers Kent Overstreet
2025-02-13 18:45 ` [PATCH 10/18] bcachefs: Advance bch_alloc.oldest_gen if no stale pointers Kent Overstreet
2025-02-13 18:45 ` [PATCH 11/18] bcachefs: bcachefs_metadata_version_stripe_backpointers Kent Overstreet
2025-02-13 18:45 ` [PATCH 12/18] bcachefs: bcachefs_metadata_version_stripe_lru Kent Overstreet
2025-02-13 18:45 ` [PATCH 13/18] bcachefs: ec_stripe_delete() uses new stripe lru Kent Overstreet
2025-02-13 18:45 ` [PATCH 14/18] bcachefs: get_existing_stripe() " Kent Overstreet
2025-02-13 18:46 ` [PATCH 15/18] bcachefs: We no longer read stripes into memory at startup Kent Overstreet
2025-02-13 18:46 ` [PATCH 16/18] bcachefs: Kill dirent_occupied_size() Kent Overstreet
2025-02-17  1:49   ` Hongbo Li
2025-02-13 18:46 ` [PATCH 17/18] bcachefs: Split out dirent alloc and name initialization Kent Overstreet
2025-02-13 18:46 ` [PATCH 18/18] bcachefs: bcachefs_metadata_version_casefolding Kent Overstreet
2025-02-21 18:26   ` Gabriel de Perthuis [this message]
2025-02-22 14:07     ` [PATCH] bcachefs: Use flexible arrays in dirent Kent Overstreet

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