From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794050038; b=ZRFrDiF7eZ39XY594UZ9ITNWiIlsAwSzI+6tSmsJiomzYj9LbMdJ+ch+ooy9f9cPFBBV Z27YmPquCxdyfhD/zpEZmJnFbx8d8LLZ29dwbhd5B+sScf1+8vA8ms62EKkvVRzsix2jS Uf+9+mrNpNqgZrsNX2iZaT92096dLXS8WeDkbZZBS82/9vlzlPu9mryP7KdF3RvL+7rYi fsXopT3ei05NGMfcd6Yd+9PEzG8xnyVeRWnONAW9G/gklSurwjrzdOkx4B90eopR5oXay DbL3bqdCMYunJvcD3qpv4ew/Tk0G4hvcpQ81rVXhWCoLRcUaCOEG3QnYXOoUEdFsx5g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794050038; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=xn9Uo9+O6y/9flSD1Eb56yiDy+Q1RutU5o1EKiC5BCo=; b=sSvgsemLV+LlSt2avU56UJf05qXetoTOahlPZ6hv1Lpn87D1cl2PcBFxbnGhHNwdmHFp nMUx8mueg9nJpFfYgdWnEmVm2Pj20k7CUZ0s4QISp+J4GqSX1d4VzXX7CrTdQ1Xdahe/2 0gmO+3T/2F+5Wo/iQMBHBWruhIGVEiVzy6kNH5pmwZxZGgwmDtjfPu6pYErtL61+khlkA FZW37lZmGmC1gWGLm1oG7t0PAxofzUfDQnPbJtXRCX9DvxhMvKb3N8C/EnHs9RcbsWkZ2 CniNwl6+NcKPu3zaZJcy0Yg7P7K9oxYJ7sF+8jybgj2uYHp/Jg9AjmY3XZZkmj80I7A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cPGGf2er; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 457E9606A32C for ; Sat, 7 Nov 2026 11:13:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cPGGf2er Received: by smtp.kernel.org (Postfix) with ESMTPSA id B83AE1F0089F; Sat, 7 Nov 2026 11:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794050038; bh=xn9Uo9+O6y/9flSD1Eb56yiDy+Q1RutU5o1EKiC5BCo=; h=From:To:Cc:Subject:Date; b=cPGGf2erAsIcTXBYlPZDXb4Vv52iRW4xSfIyeoYUhMb5qWjoNVesVQbpWQTCdLPmO 7Ga8B0h2q++9Ara883tLx4fxP/c/w+eC9SoVe6+66VV5RTaDbIY91uA2j2jWd/wxi7 r+4dzznrVytfAGTnQixkQ2G0ZylTVGFmrU10nNgbPJv0AVtrLCvzY145efIyrSupnJ V+fcBUr1sz1JD0rUdLRX1xG5pB1r3WPM7NFHsYUjz60bnX49tc/zwzjZez297Ad7NP w2Y4FOeWkmK+uMa3wqEar9xmEp+W9MtGYUIoT1itIqQYHjbsVvt5+gjnd/WpkRaIXt lTrucBUb9//Uw== From: Sasha Levin To: 4ncienth@gmail.com, brauner@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] splice: avoid stale f_pos writeback on error" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:13:56 -0500 Message-ID: <20261107061356-failed-5.15-79b496ebe382@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 79b496ebe382866e3a05090b7dc9ae95e85e65b2 # git commit -s git send-email --to '' --in-reply-to '20261107061356-failed-5.15-79b496ebe382@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 79b496ebe382866e3a05090b7dc9ae95e85e65b2 Mon Sep 17 00:00:00 2001 From: Daehyeon Ko <4ncienth@gmail.com> Date: Sun, 18 Oct 2026 14:17:08 +0900 Subject: [PATCH] splice: avoid stale f_pos writeback on error do_splice() snapshots an implicit file position before calling the splice helper. Since splice does not take f_pos_lock, another operation on the same open file description can update f_pos while the helper is blocked. If the helper then fails, the unconditional writeback restores the stale snapshot. For a directory without ->splice_read, a file-to-pipe splice fails with -EINVAL. A concurrent directory mutation and getdents() call can advance f_pos and refresh the filesystem's revalidation cookie before that failure restores only the old position. The next ext2 readdir can then trust an offset inside a directory entry and copy data from the adjacent page to userspace. Only update an implicit file position when splice returns a non-negative result, matching read and write. Keep explicit offset updates unchanged. Fixes: 7995bd287134 ("splice: don't pass the address of ->f_pos to methods") Cc: stable@vger.kernel.org Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Link: https://patch.msgid.link/20261018051708.2422394-1-4ncienth@gmail.com Signed-off-by: Christian Brauner (Amutable) --- fs/splice.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index bc243ab8dc431..f4bce35890671 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1377,10 +1377,10 @@ ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out, ret = do_splice_from(ipipe, out, &offset, len, flags); file_end_write(out); - if (!off_out) - out->f_pos = offset; - else + if (off_out) *off_out = offset; + else if (ret >= 0) + out->f_pos = offset; } else if (opipe) { if (off_out) return -ESPIPE; @@ -1401,10 +1401,10 @@ ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out, ret = splice_file_to_pipe(in, opipe, &offset, len, flags); - if (!off_in) - in->f_pos = offset; - else + if (off_in) *off_in = offset; + else if (ret >= 0) + in->f_pos = offset; } else { ret = -EINVAL; } -- 2.53.0