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 46C8F2FD7BE; Sun, 1 Mar 2026 01:52:20 +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=1772329940; cv=none; b=jydjZwDnVWViFPy4kwQgLicC74h2V3k986Nx29TX6HRaJfacq88CJP74KaHMcvnCgf7UJ0cWkGvYJIoFP3OKB//15iOV0T2U0829CvVCoXy2I6TyumYuLhduYbhAgaOfUuiVuumjT+uRs3uPmMGiTANZBC3Iqc78HYW4RY6k0Do= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772329940; c=relaxed/simple; bh=8lbF1j8bYc2jjw1q7zHSl0yiArpqCszERv6Ckuw9lKc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ExxbfcSDRbDj71ggWuDpT/XZ5LqAKnLEp8jMJEjH0nX+DwT0Qrz9KJE7wWPeN1KIShBeOg4K7JEBYEpEMv+EOjbgrg7oTwHd+N//5udFikheFf3EAohq5xIRDhA1XQLTBaY7pmwinwKT7C2aqD4i6DbWBreHBYInEYthpAI4z20= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rRzobopH; 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="rRzobopH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F4ADC19421; Sun, 1 Mar 2026 01:52:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772329939; bh=8lbF1j8bYc2jjw1q7zHSl0yiArpqCszERv6Ckuw9lKc=; h=From:To:Cc:Subject:Date:From; b=rRzobopH0/8uqv36Pb+6xjDCWg2IwJlsVlKBCweYPBOfxYd3xlKYRssjWcbZY43XG /kbQFYNiSGU7eiXSCYS1H5Z55QCdo6rmoUvsxh9KiU4tKzXXjBtr2zU0mv173/go5f PDGXIIxaXD0F7t61aP1S3lCvNxMxhPIPru8N0gngiiAli5m2kvde2Ky8GrQ82cf7Ie DJuWv88llaIe81/CIYcekNUaeSGu+RQSUTN9MgqJI+UbjRFW/GlE2xmVpKQv8hwKj0 wVrGApXSbV1PDWauTyLf3Ets2L2Vyz7mrOOEgwh+dnsr+OfbPTPgKp56E/TGeQYovC dmbiC5bxQCSBw== From: Sasha Levin To: stable@vger.kernel.org, jinpu.wang@ionos.com Cc: Yu Kuai , linux-raid@vger.kernel.org Subject: FAILED: Patch "md/bitmap: fix GPF in write_page caused by resize race" failed to apply to 5.15-stable tree Date: Sat, 28 Feb 2026 20:52:17 -0500 Message-ID: <20260301015218.1718763-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review 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 . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 46ef85f854dfa9d5226b3c1c46493d79556c9589 Mon Sep 17 00:00:00 2001 From: Jack Wang Date: Tue, 20 Jan 2026 11:24:56 +0100 Subject: [PATCH] md/bitmap: fix GPF in write_page caused by resize race A General Protection Fault occurs in write_page() during array resize: RIP: 0010:write_page+0x22b/0x3c0 [md_mod] This is a use-after-free race between bitmap_daemon_work() and __bitmap_resize(). The daemon iterates over `bitmap->storage.filemap` without locking, while the resize path frees that storage via md_bitmap_file_unmap(). `quiesce()` does not stop the md thread, allowing concurrent access to freed pages. Fix by holding `mddev->bitmap_info.mutex` during the bitmap update. Link: https://lore.kernel.org/linux-raid/20260120102456.25169-1-jinpu.wang@ionos.com Closes: https://lore.kernel.org/linux-raid/CAMGffE=Mbfp=7xD_hYxXk1PAaCZNSEAVeQGKGy7YF9f2S4=NEA@mail.gmail.com/T/#u Cc: stable@vger.kernel.org Fixes: d60b479d177a ("md/bitmap: add bitmap_resize function to allow bitmap resizing.") Signed-off-by: Jack Wang Signed-off-by: Yu Kuai --- drivers/md/md-bitmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index dbe4c4b9a1daf..1d4a050dab3ab 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2453,6 +2453,7 @@ static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks, memcpy(page_address(store.sb_page), page_address(bitmap->storage.sb_page), sizeof(bitmap_super_t)); + mutex_lock(&bitmap->mddev->bitmap_info.mutex); spin_lock_irq(&bitmap->counts.lock); md_bitmap_file_unmap(&bitmap->storage); bitmap->storage = store; @@ -2560,7 +2561,7 @@ static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks, set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY); } spin_unlock_irq(&bitmap->counts.lock); - + mutex_unlock(&bitmap->mddev->bitmap_info.mutex); if (!init) { __bitmap_unplug(bitmap); bitmap->mddev->pers->quiesce(bitmap->mddev, 0); -- 2.51.0