From patchwork Thu Nov 11 08:46:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ajay Garg X-Patchwork-Id: 12614397 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F3D2C433F5 for ; Thu, 11 Nov 2021 08:46:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2B49761208 for ; Thu, 11 Nov 2021 08:46:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2B49761208 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 9FA006B009F; Thu, 11 Nov 2021 03:46:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9A8876B00A0; Thu, 11 Nov 2021 03:46:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 870B96B00A1; Thu, 11 Nov 2021 03:46:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0031.hostedemail.com [216.40.44.31]) by kanga.kvack.org (Postfix) with ESMTP id 77FCA6B009F for ; Thu, 11 Nov 2021 03:46:31 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2D38282ED2D9 for ; Thu, 11 Nov 2021 08:46:31 +0000 (UTC) X-FDA: 78796018182.28.8E725F8 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) by imf06.hostedemail.com (Postfix) with ESMTP id CA290801A8AE for ; Thu, 11 Nov 2021 08:46:30 +0000 (UTC) Received: by mail-pj1-f47.google.com with SMTP id n15-20020a17090a160f00b001a75089daa3so4081287pja.1 for ; Thu, 11 Nov 2021 00:46:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=J9tytTC89tIbQkkTkBO8DMvoL6kQDxHyRTJb1T6FR4I=; b=gJKdUH+boe+03Lj9B0dpLRiHMIx7CCyfV9fm4zLuWRj4xiB/R765QusNMWZZz0b1Ne NBV5FHQ9VHA1Yo1Z81pEZDDbBsMVZJpWYrPmxIJP2BvsyQ6WvWPTIhYo7oMSyQWor05f nuNQxGKy1vRwuPMjVSTlnHFg8TmYPm3+9yi8ZT1t2lD4GSp2zRHv8ZxMR/UrKiWXD7KY OVLq9lXjT4fR8v9cQvr95EQV+rbZRvZmxZ+eI2cZkil9QOTAzl/JvSOoV8gwM9XuPArg 0/sl8wOtp1HIJ50ZsTITO4wtiaqI18IJ3K+9um6XsDNIYzh0rSN8vDZOdSBuyjYq/uxp SLkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=J9tytTC89tIbQkkTkBO8DMvoL6kQDxHyRTJb1T6FR4I=; b=rMtz9hrMYQc3iq0Pzv5MluD8Bw+6vhozR8381MGzlQ/HMUE5T/eZGpo3kbCZSbvTTY TshQyy5ijsjdn1xXhrR7OSWfpn3R4Deev7W5UvVKzuYNqzF8AUr3cajTsPvpdkrFnwMM PQvZ581oJiDyf+gvVNWCx4WMrX4WPtZe34Y+4sL9W1zZb2U0N4KDdI8q0UNUl1KivGQK j6ATn3obW2o57KSA0Z+q8+zTlpvxNEhVmqQ4nWqXRaBDPkS4mc2AaE0EA/+9hLKWGueB No+PNDQVNwrdLDmc/RVf7umZkYlkWvdTqx85U3+039b/6VB0q98/aOM8nIosZscVk25b Erbw== X-Gm-Message-State: AOAM533pvqUeWXJtNo0zZ8RYiS0FKMK+4LwBNaAvvq3pJYEsc4c4C86E 09mSmPdOfGF+ObmIhSyw/2U= X-Google-Smtp-Source: ABdhPJycXbgOGJgNgY9qJNh952ZDv0BKh88rCcOWEt7rqPB5PmStXpRZZYS9V+FLZr92v/im7wlPGw== X-Received: by 2002:a17:903:1248:b0:13f:cd7d:69eb with SMTP id u8-20020a170903124800b0013fcd7d69ebmr6376481plh.23.1636620389666; Thu, 11 Nov 2021 00:46:29 -0800 (PST) Received: from host-x86-64.. ([122.161.243.27]) by smtp.gmail.com with ESMTPSA id v1sm2107306pfg.204.2021.11.11.00.46.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Nov 2021 00:46:29 -0800 (PST) From: Ajay Garg To: hughd@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Ajay Garg Subject: [PATCH] mm: shmem: do not call PageHWPoison on a ERR-page Date: Thu, 11 Nov 2021 14:16:17 +0530 Message-Id: <20211111084617.6746-1-ajaygargnsit@gmail.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: CA290801A8AE X-Stat-Signature: p5sq6xwuhttwkuswz77athkzdud4yjwn Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=gJKdUH+b; spf=pass (imf06.hostedemail.com: domain of ajaygargnsit@gmail.com designates 209.85.216.47 as permitted sender) smtp.mailfrom=ajaygargnsit@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1636620390-675281 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: commit b9d02f1bdd98 ("mm: shmem: don't truncate page if memory failure happens") introduced a PageHWPoison(page) call in "shmem_read_mapping_page_gfp" in shmem.c. Now, if "shmem_getpage_gfp" returns an error, page is set to ERR-page. Therafter, calling PageHWPoison() on this ERR-page, causes KASAN to OOP the kernel : ############################# BUG: unable to handle page fault for address: fffffffffffffff4 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 18e019067 P4D 18e019067 PUD 18e01b067 PMD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN PTI CPU: 0 PID: 4836 Comm: MATLAB Not tainted 5.15.0+ #18 Hardware name: Dell Inc. Latitude E6320/0GJF11, BIOS A19 11/14/2013 RIP: 0010:shmem_read_mapping_page_gfp+0xd3/0x140 Code: 4c 89 ff e8 6f eb ff ff 5a 59 85 c0 74 64 48 63 d8 48 89 5d 98 be 08 00 00 00 48 89 df e8 e5 67 0c 00 48 89 df e8 6d 5c 0c 00 <48> 8b 13 48 c7 c0 fb ff ff ff f7 c2 00 00 80 00 74 30 48 ba 00 00 RSP: 0018:ffff88806b33f998 EFLAGS: 00010246 RAX: 0000000000000000 RBX: fffffffffffffff4 RCX: ffffffffb7a37ba3 RDX: 0000000000000003 RSI: dffffc0000000000 RDI: fffffffffffffff4 RBP: ffff88806b33fa20 R08: 1ffffffffffffffe R09: fffffffffffffffb R10: fffffbffffffffff R11: 0000000000000001 R12: 1ffff1100d667f33 R13: 00000000001120d2 R14: 00000000000005db R15: ffff88814e64e2d8 FS: 00007f379a384640(0000) GS:ffff888161a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffff4 CR3: 00000000269dc004 CR4: 00000000000606f0 Call Trace: ? shmem_fault+0x480/0x480 ? __cond_resched+0x1c/0x30 ? __kasan_check_read+0x11/0x20 shmem_get_pages+0x3a4/0xa70 [i915] ? shmem_writeback+0x3b0/0x3b0 [i915] ? i915_gem_object_wait_reservation+0x330/0x560 [i915] ... ... ################################ So, we proceed with PageHWPoison() call, only if the page is not a ERR-page. P.S. : Alternative (optimised) solution : =========================================== We could save some CPU cycles, if we directly replace if (error) page = ERR_PTR(error); else unlock_page(page); with if (error) return ERR_PTR(error); Fixes: b9d02f1bdd98 ("mm: shmem: don't truncate page if memory failure happens") Signed-off-by: Ajay Garg --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index 23c91a8beb78..427863cbf0dc 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -4222,7 +4222,7 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, else unlock_page(page); - if (PageHWPoison(page)) + if (!IS_ERR(page) && PageHWPoison(page)) page = ERR_PTR(-EIO); return page;