From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C2BC83F3283; Fri, 9 Oct 2026 22:04:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791583478; cv=none; b=nO77U2VT+6+XOwD1b9oUTlDhCoVEA4m47CoUwQ2zq5rLskmEF5KPYyzo6XsNhxeAgU0AZO8cxFu8Du32FS2cZagHI9rsxmhSTj5C1Qm3k0wX0MW8p2NUTbaoaGItqGyutr4xKIvP1t/HfOoYhagQ09q5nEDh5W13iOwjQH22be8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791583478; c=relaxed/simple; bh=UI36m8o3KOZtsOGxQ+vrTJPlLyGT/pg5OuG8AK7GTQg=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=hcqsYm8WcHTRjdt07bNKNrbQJ98/d8VKwQa+2ScGbar3YMRgmrf2n19ndBlxsPyrB6je6cp5Nx2gNd2mHTW7NnFnRpba14yWc/ahG70+eom8l2DUqdDFAi/GU002Lc88XuAH4P88C3S0+ryclIO+hHNtcyBv9KyWB1oVUwiWQWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TYKRy93Y; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TYKRy93Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 650601F000FF; Fri, 9 Oct 2026 22:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791583477; bh=UI36m8o3KOZtsOGxQ+vrTJPlLyGT/pg5OuG8AK7GTQg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=TYKRy93YZSbVeGyD0xbCL8nquwHbNbLgBJlAS7N+yl5G4RYdl8T0TEIR/gHrKkPli B1zJ9TbAfv/tCpc3YBbysAIsK0gf51nbfhoBjhmcGT/Olr7YgT85dvXtjM/wJVdabu 79IqaeHUclVVRCd8G8bKdRk8r1zik8Irf20vTjKB6384/fck/UItaxF+uL4ctr4hUQ QbJuZBaQDw2AvSxNRTQnQtVTlkUXUd5/zwx8zAjTEdaapwVib1oIT/aPAjro3J224a 0+WSau2DQ/6uteS21k64qsvRzJfqg8JJvdVszRIDgjqYXyEwVDDzQnoC42OLgoo87q ygjicUQ6uQt1g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 1/8] ext4: free the sbi after a grace period Reply-To: sashiko-reviews@lists.linux.dev To: "Christian Brauner" Cc: linux-ext4@vger.kernel.org, linux-trace-kernel@vger.kernel.org, tytso@mit.edu In-Reply-To: <20261009-work-fixes-rcu-v1-1-7446d2d335e6@kernel.org> References: <20261009-work-fixes-rcu-v1-0-7446d2d335e6@kernel.org> <20261009-work-fixes-rcu-v1-1-7446d2d335e6@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 09 Oct 2026 22:04:36 +0000 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > ext4_get_link() follows a symlink that keeps its target in a data block > in rcu pathwalk mode with ext4_getblk(EXT4_GET_BLOCKS_CACHED_NOWAIT). > That reads s_mount_state in the ASSERT() of ext4_getblk() and again in > ext4_es_lookup_extent(), and the lookup bumps the extent status hit or > miss counter, all through sb->s_fs_info. >=20 > ext4_put_super() destroys those counters, clears sb->s_fs_info and frees > the sbi without waiting for a grace period. A pathwalk that is still in > ext4_get_link() when the last reference to the mount goes away then > dereferences a NULL s_fs_info, the freed sbi or the destroyed percpu > counters. >=20 > With a pathwalk held up in ext4_get_link() while the last reference > goes away: >=20 > [ ... ] > in ext4_put_super(), the counters go with the sbi. >=20 > Fixes: 6493792d3299 ("ext4: convert symlink external data block mapping t= o bdev") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Brauner (Amutable) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261009-work-fixes= -rcu-v1-0-7446d2d335e6@kernel.org?part=3D1