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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 31 Jan 2019 07:15:07 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0V7F6tN55378120 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 31 Jan 2019 07:15:06 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D50C74C046; Thu, 31 Jan 2019 07:15:04 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5E7D14C040; Thu, 31 Jan 2019 07:15:01 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.8.84]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 31 Jan 2019 07:15:01 +0000 (GMT) Date: Thu, 31 Jan 2019 09:14:59 +0200 From: Mike Rapoport To: Christophe Leroy Cc: linux-mm@kvack.org, Rich Felker , linux-ia64@vger.kernel.org, devicetree@vger.kernel.org, Catalin Marinas , Heiko Carstens , x86@kernel.org, linux-mips@vger.kernel.org, Max Filippov , Guo Ren , sparclinux@vger.kernel.org, Christoph Hellwig , linux-s390@vger.kernel.org, linux-c6x-dev@linux-c6x.org, Yoshinori Sato , Richard Weinberger , linux-sh@vger.kernel.org, Russell King , kasan-dev@googlegroups.com, Geert Uytterhoeven , Mark Salter , Dennis Zhou , Matt Turner , linux-snps-arc@lists.infradead.org, uclinux-h8-devel@lists.sourceforge.jp, Petr Mladek , linux-xtensa@linux-xtensa.org, linux-alpha@vger.kernel.org, linux-um@lists.infradead.org, linux-m68k@lists.linux-m68k.org, Rob Herring , Greentime Hu , xen-devel@lists.xenproject.org, Stafford Horne , Guan Xuetao , linux-arm-kernel@lists.infradead.org, Michal Simek , Tony Luck , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Burton , Vineet Gupta , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , openrisc@lists.librecores.org, Stephen Rothwell Subject: Re: [PATCH v2 19/21] treewide: add checks for the return value of memblock_alloc*() References: <1548057848-15136-1-git-send-email-rppt@linux.ibm.com> <1548057848-15136-20-git-send-email-rppt@linux.ibm.com> <20190131064139.GB28876@rapoport-lnx> <8838f7ab-998b-6d78-02a8-a53f8a3619d9@c-s.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19013107-0020-0000-0000-0000030F29F7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19013107-0021-0000-0000-000021602B4F Message-Id: <20190131071459.GC28876@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-31_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901310057 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: On Thu, Jan 31, 2019 at 08:07:29AM +0100, Christophe Leroy wrote: > > > Le 31/01/2019 à 07:44, Christophe Leroy a écrit : > > > > > >Le 31/01/2019 à 07:41, Mike Rapoport a écrit : > >>On Thu, Jan 31, 2019 at 07:07:46AM +0100, Christophe Leroy wrote: > >>> > >>> > >>>Le 21/01/2019 à 09:04, Mike Rapoport a écrit : > >>>>Add check for the return value of memblock_alloc*() functions and call > >>>>panic() in case of error. > >>>>The panic message repeats the one used by panicing memblock > >>>>allocators with > >>>>adjustment of parameters to include only relevant ones. > >>>> > >>>>The replacement was mostly automated with semantic patches like the one > >>>>below with manual massaging of format strings. > >>>> > >>>>@@ > >>>>expression ptr, size, align; > >>>>@@ > >>>>ptr = memblock_alloc(size, align); > >>>>+ if (!ptr) > >>>>+     panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__, > >>>>size, align); > >>>> > >>>>Signed-off-by: Mike Rapoport > >>>>Reviewed-by: Guo Ren              # c-sky > >>>>Acked-by: Paul Burton          # MIPS > >>>>Acked-by: Heiko Carstens # s390 > >>>>Reviewed-by: Juergen Gross          # Xen > >>>>--- > >>> > >>>[...] > >>> > >>>>diff --git a/mm/sparse.c b/mm/sparse.c > >>>>index 7ea5dc6..ad94242 100644 > >>>>--- a/mm/sparse.c > >>>>+++ b/mm/sparse.c > >>> > >>>[...] > >>> > >>>>@@ -425,6 +436,10 @@ static void __init sparse_buffer_init(unsigned > >>>>long size, int nid) > >>>>          memblock_alloc_try_nid_raw(size, PAGE_SIZE, > >>>>                          __pa(MAX_DMA_ADDRESS), > >>>>                          MEMBLOCK_ALLOC_ACCESSIBLE, nid); > >>>>+    if (!sparsemap_buf) > >>>>+        panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d > >>>>from=%lx\n", > >>>>+              __func__, size, PAGE_SIZE, nid, __pa(MAX_DMA_ADDRESS)); > >>>>+ > >>> > >>>memblock_alloc_try_nid_raw() does not panic (help explicitly says: > >>>Does not > >>>zero allocated memory, does not panic if request cannot be satisfied.). > >> > >>"Does not panic" does not mean it always succeeds. > > > >I agree, but at least here you are changing the behaviour by making it > >panic explicitly. Are we sure there are not cases where the system could > >just continue functionning ? Maybe a WARN_ON() would be enough there ? > > Looking more in details, it looks like everything is done to live with > sparsemap_buf NULL, all functions using it check it so having it NULL > shouldn't imply a panic I believe, see code below. You are right, I'm preparing the fix right now. > static void *sparsemap_buf __meminitdata; > static void *sparsemap_buf_end __meminitdata; > > static void __init sparse_buffer_init(unsigned long size, int nid) > { > WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */ > sparsemap_buf = > memblock_alloc_try_nid_raw(size, PAGE_SIZE, > __pa(MAX_DMA_ADDRESS), > MEMBLOCK_ALLOC_ACCESSIBLE, nid); > sparsemap_buf_end = sparsemap_buf + size; > } > > static void __init sparse_buffer_fini(void) > { > unsigned long size = sparsemap_buf_end - sparsemap_buf; > > if (sparsemap_buf && size > 0) > memblock_free_early(__pa(sparsemap_buf), size); > sparsemap_buf = NULL; > } > > void * __meminit sparse_buffer_alloc(unsigned long size) > { > void *ptr = NULL; > > if (sparsemap_buf) { > ptr = PTR_ALIGN(sparsemap_buf, size); > if (ptr + size > sparsemap_buf_end) > ptr = NULL; > else > sparsemap_buf = ptr + size; > } > return ptr; > } > > > Christophe > -- Sincerely yours, Mike.