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Sun, 12 Aug 2018 20:25:56 -0700 (PDT) Received: from localhost.localdomain ([2402:f000:1:4414:1c12:d766:6865:caf9]) by smtp.gmail.com with ESMTPSA id v30-v6sm27095721pgn.80.2018.08.12.20.25.54 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 12 Aug 2018 20:25:56 -0700 (PDT) From: Jia-Ju Bai To: dwmw2@infradead.org Subject: [PATCH] fs: jffs2: fix a sleep-in-atomic-context bug in jffs2_alloc_refblock() Date: Mon, 13 Aug 2018 11:25:47 +0800 Message-Id: <20180813032547.3156-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180812_202607_581302_B094B1AB X-CRM114-Status: GOOD ( 11.78 ) X-Spam-Score: 0.1 (/) X-Spam-Report: SpamAssassin version 3.4.1 on bombadil.infradead.org summary: Content analysis details: (0.1 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [2607:f8b0:400e:c01:0:0:0:242 listed in] [list.dnswl.org] 0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in digit (baijiaju1990[at]gmail.com) 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (baijiaju1990[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jia-Ju Bai , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org The kernel may sleep with holding a spin lock. The function call paths (from bottom to top) in Linux-4.16 are: [FUNC] kmem_cache_alloc(GFP_KERNEL) fs/jffs2/malloc.c, 188: kmem_cache_alloc in jffs2_alloc_refblock fs/jffs2/malloc.c, 221: jffs2_alloc_refblock in jffs2_prealloc_raw_node_refs fs/jffs2/wbuf.c, 164: jffs2_prealloc_raw_node_refs in jffs2_block_refile fs/jffs2/wbuf.c, 927: jffs2_block_refile in jffs2_flash_writev fs/jffs2/wbuf.c, 924: spin_lock in jffs2_flash_writev To fix it, GFP_KERNEL in kmem_cache_alloc() is replaced with GFP_ATOMIC. This is found by my static analysis tool (DSAC). Signed-off-by: Jia-Ju Bai --- fs/jffs2/malloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/jffs2/malloc.c b/fs/jffs2/malloc.c index ce1189793288..66496ef09716 100644 --- a/fs/jffs2/malloc.c +++ b/fs/jffs2/malloc.c @@ -185,7 +185,7 @@ static struct jffs2_raw_node_ref *jffs2_alloc_refblock(void) { struct jffs2_raw_node_ref *ret; - ret = kmem_cache_alloc(raw_node_ref_slab, GFP_KERNEL); + ret = kmem_cache_alloc(raw_node_ref_slab, GFP_ATOMIC); if (ret) { int i = 0; for (i=0; i < REFS_PER_BLOCK; i++) {