From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1368C340A59 for ; Sat, 28 Feb 2026 17:51:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772301097; cv=none; b=aYsI+qtpdiNu204fzCrjEymSbscUktbMPAaB5avbShVO+vrNqZ1CAI/ES33DcCgQQH4iE6Y1jTRRlwAGXGfBXLAkY3pJFPBHnxOXwr5MZeie/bAi3ROket5UGnBTeO6oAsuj0hIA++HWWMGHIjGPvs2ws4Wr4Ls6vCEqzj+84Hg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772301097; c=relaxed/simple; bh=MnePM5clM5bMJt3NTSI6XRI2xXw327QZDD7Xn1DK26Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XSZpHul76865Oe9B8z7CF5QeKER7HaMUE7sJHTaQ++vZdfRbLW9E6ry+tBrGTFF9TevozlilDjtmLX1vcRMqoG0HP3Z2+++9IPPU8aUOYKpTOnaFwEHNYUl+5XnVYrkoQ1VnNnO97Y8RJ79D63A6OLrPHl/30a9syxHsg+rSIRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LFhVfdj3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LFhVfdj3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B54FC19425; Sat, 28 Feb 2026 17:51:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772301096; bh=MnePM5clM5bMJt3NTSI6XRI2xXw327QZDD7Xn1DK26Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LFhVfdj3Fnhciw2Q8F9f9wHlkuZ9h4bNjiKWFiH9Yydjw0KTw0hQ1PwEL0qQaB1nY rYGV+BlShq0Kn/qtU+zBYqRFnDWtD9XCAMVUzBSr8hvqKlCImMEiNEJ/17UxKrO9eH ZRd0QvO6294mwBTkEcwzTO+zFCG4RN43vB9TBSpHVEx5CQzldQC8CJ2AhL3A9G5+fd NsPNz91pD8Qk7kbQjBoLYj1NVVw49S+IlcdgSe7Cf+gYctAZPgSE/oVHgbT3N3l7EF od9D/BWSpvBUNRPvwPmrN2DaEMWqVnjV4B0UbCmg3HMbloSshSRji/ibhXpuvu0REP hL13yrhkdHqsA== From: Sasha Levin To: patches@lists.linux.dev Cc: Baokun Li , Zhang Yi , Jan Kara , Theodore Ts'o , Sasha Levin Subject: [PATCH 6.18 248/752] ext4: move ext4_percpu_param_init() before ext4_mb_init() Date: Sat, 28 Feb 2026 12:39:19 -0500 Message-ID: <20260228174750.1542406-248-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228174750.1542406-1-sashal@kernel.org> References: <20260228174750.1542406-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Baokun Li [ Upstream commit 270564513489d98b721a1e4a10017978d5213bff ] When running `kvm-xfstests -c ext4/1k -C 1 generic/383` with the `DOUBLE_CHECK` macro defined, the following panic is triggered: ================================================================== EXT4-fs error (device vdc): ext4_validate_block_bitmap:423: comm mount: bg 0: bad block bitmap checksum BUG: unable to handle page fault for address: ff110000fa2cc000 PGD 3e01067 P4D 3e02067 PUD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 2386 Comm: mount Tainted: G W 6.18.0-gba65a4e7120a-dirty #1152 PREEMPT(none) RIP: 0010:percpu_counter_add_batch+0x13/0xa0 Call Trace: ext4_mark_group_bitmap_corrupted+0xcb/0xe0 ext4_validate_block_bitmap+0x2a1/0x2f0 ext4_read_block_bitmap+0x33/0x50 mb_group_bb_bitmap_alloc+0x33/0x80 ext4_mb_add_groupinfo+0x190/0x250 ext4_mb_init_backend+0x87/0x290 ext4_mb_init+0x456/0x640 __ext4_fill_super+0x1072/0x1680 ext4_fill_super+0xd3/0x280 get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x29/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4f6/0x6b0 do_syscall_64+0x50/0x1f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ================================================================== This issue can be reproduced using the following commands: mkfs.ext4 -F -q -b 1024 /dev/sda 5G tune2fs -O quota,project /dev/sda mount /dev/sda /tmp/test With DOUBLE_CHECK defined, mb_group_bb_bitmap_alloc() reads and validates the block bitmap. When the validation fails, ext4_mark_group_bitmap_corrupted() attempts to update sbi->s_freeclusters_counter. However, this percpu_counter has not been initialized yet at this point, which leads to the panic described above. Fix this by moving the execution of ext4_percpu_param_init() to occur before ext4_mb_init(), ensuring the per-CPU counters are initialized before they are used. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Link: https://patch.msgid.link/20251209133116.731350-1-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/super.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4ef5590c73fda..b5774f4101045 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5565,6 +5565,10 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) clear_opt2(sb, MB_OPTIMIZE_SCAN); } + err = ext4_percpu_param_init(sbi); + if (err) + goto failed_mount5; + err = ext4_mb_init(sb); if (err) { ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)", @@ -5580,10 +5584,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) sbi->s_journal->j_commit_callback = ext4_journal_commit_callback; - err = ext4_percpu_param_init(sbi); - if (err) - goto failed_mount6; - if (ext4_has_feature_flex_bg(sb)) if (!ext4_fill_flex_info(sb)) { ext4_msg(sb, KERN_ERR, @@ -5665,8 +5665,8 @@ failed_mount8: __maybe_unused failed_mount6: ext4_mb_release(sb); ext4_flex_groups_free(sbi); - ext4_percpu_param_destroy(sbi); failed_mount5: + ext4_percpu_param_destroy(sbi); ext4_ext_release(sb); ext4_release_system_zone(sb); failed_mount4a: -- 2.51.0