Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751601Ab3EIHIz (ORCPT ); Thu, 9 May 2013 03:08:55 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:29351 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198Ab3EIHIw (ORCPT ); Thu, 9 May 2013 03:08:52 -0400 Message-ID: <518B4B5F.9040900@huawei.com> Date: Thu, 9 May 2013 15:08:15 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: Dave Jones CC: Linus Torvalds , Linux Kernel , , , , Naoya Horiguchi Subject: Re: SHM oops in newseg() References: <20130509043532.GA28235@redhat.com> In-Reply-To: <20130509043532.GA28235@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3259 Lines: 95 Cc: Naoya Horiguchi On 2013/5/9 12:35, Dave Jones wrote: > Just saw this on v3.9-11789-ge0fd9af while fuzz-testing. > > [ 163.917836] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > [ 163.918984] IP: [] newseg+0x10d/0x390 The patch below should fix it. =========================== [PATCH] shm: fix null pointer deref when userspace specifies invalid hugepage size Dave reported an oops triggered by trinity: [ 163.917836] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 163.918984] IP: [] newseg+0x10d/0x390 [ 163.919705] PGD cf8c1067 PUD cf8c2067 PMD 0 [ 163.920326] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 163.929949] CPU: 2 PID: 7636 Comm: trinity-child2 Not tainted 3.9.0+#67 ... [ 163.953629] Call Trace: [ 163.957706] [] ipcget+0x182/0x380 [ 163.962123] [] ?trace_hardirqs_on_caller+0x115/0x1e0 [ 163.966752] [] SyS_shmget+0x5a/0x60 [ 163.971163] [] ? shm_close+0x140/0x140 [ 163.975590] [] ? shm_release+0x50/0x50 [ 163.979991] [] ? shm_get_unmapped_area+0x20/0x20 [ 163.984499] [] tracesys+0xdd/0xe2 This bug was introduced by commit af73e4d9506d3b797509f3c030e7dcd554f7d9c4 ("hugetlbfs: fix mmap failure in unaligned size request"). Reported-by: Dave Jones Cc: Signed-off-by: Li Zefan --- Previously it would return -ENODEV, but seems -EINVAL is more appropriate. --- ipc/shm.c | 8 +++++++- mm/mmap.c | 8 ++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index 34af1fe..7e199fa 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -493,7 +493,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) if (shmflg & SHM_HUGETLB) { struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); - size_t hugesize = ALIGN(size, huge_page_size(hs)); + size_t hugesize; + + if (!hs) { + error = -EINVAL; + goto no_file; + } + hugesize = ALIGN(size, huge_page_size(hs)); /* hugetlb_file_setup applies strict accounting */ if (shmflg & SHM_NORESERVE) diff --git a/mm/mmap.c b/mm/mmap.c index 1ae21d6..f681e18 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1367,9 +1367,13 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, len = ALIGN(len, huge_page_size(hstate_file(file))); } else if (flags & MAP_HUGETLB) { struct user_struct *user = NULL; + struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & + SHM_HUGE_MASK); - len = ALIGN(len, huge_page_size(hstate_sizelog( - (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))); + if (!hs) + return -EINVAL; + + len = ALIGN(len, huge_page_size(hs)); /* * VM_NORESERVE is used because the reservations will be * taken when vm_ops->mmap() is called -- 1.8.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/