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 A87083016EE; Tue, 31 Mar 2026 17:07:00 +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=1774976820; cv=none; b=VZDpYfC+W/Rfknp2dK4HmzZjKgc5JysK/g59VPLPMUTasCCV3fQnqXnO6OMOe4jJOhv42EJjXuIfzA6n2Y1KU1QxBqgT6GFhpEtOIhWJNIBbWhpFKctuNdNLBRCU5rsYGthHQVw/g35eOoKJZ4ZX/RSYzVSllzc5Fr5WpEfzZ80= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976820; c=relaxed/simple; bh=ewmBQ9gGBt27Fuk/U7ilyzhrU+1KmOqyPT3eqpnpdTI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z2272J4UAfDJCyViuzCbGo7VEnopv9XH98cEOl0Fq/tyFbiFTpMm8VHvlop6bNFHUXLLDmELnKFjeC7Tz1QAnyhAvYKlLlQ9mysV97ASmO7Jejn4CFmHbQVk05P7t5bDfPg5wXQmk2vuu7cXsdjUEu3I5xJBcOExhqBqLREyEHQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DV8kX/f0; 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="DV8kX/f0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13BC1C19423; Tue, 31 Mar 2026 17:06:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774976820; bh=ewmBQ9gGBt27Fuk/U7ilyzhrU+1KmOqyPT3eqpnpdTI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DV8kX/f06nEY8qV5NwldEhOzx/u9P5dCws4VnvSmDauKeqaQsu2aP+GBQvkygu5Hb ueeubEGkweOQs7+TkMrnXtgECOejF8ecICj63Jtzoca2nN0wRxfL9bmqOdhjWtOLvO pmfmIVO1qtEty03U4LqpMxJlB4D8nHEi+UY2NCC0= 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 6.18 208/309] erofs: add GFP_NOIO in the bio completion if needed Date: Tue, 31 Mar 2026 18:21:51 +0200 Message-ID: <20260331161801.105297713@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161753.468533260@linuxfoundation.org> References: <20260331161753.468533260@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 @@ -1445,6 +1445,7 @@ static void z_erofs_decompress_kickoff(s int bios) { struct erofs_sb_info *const sbi = EROFS_SB(io->sb); + int gfp_flag; /* wake up the caller thread for sync decompression */ if (io->sync) { @@ -1477,7 +1478,9 @@ static void z_erofs_decompress_kickoff(s sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON; return; } + gfp_flag = memalloc_noio_save(); z_erofs_decompressqueue_work(&io->u.work); + memalloc_noio_restore(gfp_flag); } static void z_erofs_fill_bio_vec(struct bio_vec *bvec,