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 C655429BD87; Mon, 13 Apr 2026 16:35:33 +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=1776098133; cv=none; b=RAgiOhl6yLj0tcj6oX/m6m1dYKKadwJp1bCRhMWYTygXXud/ENSQtT1piQDJo4zBbpfXn8xfC7jqOBdsojM529g5AAj3WutGEiqzWkGIXQfgAQn22nqLBXU5fPKCIf7vECkqQ77zy3SJQC2dnCyr579xr6n19nhzFjwPXeB/cNw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776098133; c=relaxed/simple; bh=iKWG7Jvykyu2rakjYjuI90DmJ3QyPoBrs9oQFsWUhWs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ee1TSGafEZ7kQnafK+SS2hu5gt88/46VYqBHMqUw93WD0C87QXOCi4FR1A2IfhjAr7PNFYjD1shle4c8x8IkFSApl3H4nraAnyoNBJ9zV5xOdlPkGfAO+GNgjAH+/teRXfU81WoitTDWEKFVCgHjfRIwLgzpVOa5SxaaySQVWyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=K0VDGBig; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K0VDGBig" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C2AFC2BCAF; Mon, 13 Apr 2026 16:35:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776098133; bh=iKWG7Jvykyu2rakjYjuI90DmJ3QyPoBrs9oQFsWUhWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K0VDGBigzlNTaLUA+Booy/63qqeiektYucMEFuaaMg439Ji1EmLnunJ9phXA7uT3/ gLizHzhm6OXeszc9AGfNRBrnmhZPjvGv9gAVSuBpGHPMea2erKo/dXWKaMikj0a9FG ZivbSwVaj7yaE1mp+bn4Vr9k3urhqibrH+qb7W94= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gao Xiang , Jiucheng Xu , Chao Yu Subject: [PATCH 5.15 374/570] erofs: add GFP_NOIO in the bio completion if needed Date: Mon, 13 Apr 2026 17:58:25 +0200 Message-ID: <20260413155844.489668506@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiucheng Xu commit c23df30915f83e7257c8625b690a1cece94142a0 upstream. The bio completion path in the process context (e.g. dm-verity) will directly call into decompression rather than trigger another workqueue context for minimal scheduling latencies, which can then call vm_map_ram() with GFP_KERNEL. Due to insufficient memory, vm_map_ram() may generate memory swapping I/O, which can cause submit_bio_wait to deadlock in some scenarios. Trimmed down the call stack, as follows: f2fs_submit_read_io submit_bio //bio_list is initialized. mmc_blk_mq_recovery z_erofs_endio vm_map_ram __pte_alloc_kernel __alloc_pages_direct_reclaim shrink_folio_list __swap_writepage submit_bio_wait //bio_list is non-NULL, hang!!! Use memalloc_noio_{save,restore}() to wrap up this path. Reviewed-by: Gao Xiang Signed-off-by: Jiucheng Xu Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Signed-off-by: Greg Kroah-Hartman --- fs/erofs/zdata.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -782,6 +782,7 @@ static void z_erofs_decompress_kickoff(s bool sync, int bios) { struct erofs_sb_info *const sbi = EROFS_SB(io->sb); + int gfp_flag; /* wake up the caller thread for sync decompression */ if (sync) { @@ -802,7 +803,9 @@ static void z_erofs_decompress_kickoff(s sbi->opt.readahead_sync_decompress = true; return; } + gfp_flag = memalloc_noio_save(); z_erofs_decompressqueue_work(&io->u.work); + memalloc_noio_restore(gfp_flag); } static bool z_erofs_page_is_invalidated(struct page *page)