Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753162Ab3IQO5o (ORCPT ); Tue, 17 Sep 2013 10:57:44 -0400 Received: from e06smtp14.uk.ibm.com ([195.75.94.110]:33760 "EHLO e06smtp14.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752689Ab3IQO5n (ORCPT ); Tue, 17 Sep 2013 10:57:43 -0400 Date: Tue, 17 Sep 2013 16:57:34 +0200 From: Michael Holzheu To: Tejun Heo , Christoph Lameter Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: Fix bootmem error handling in pcpu_page_first_chunk() Message-ID: <20130917165734.16aa0226@holzheu> Organization: IBM X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13091714-1948-0000-0000-00000655733A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2292 Lines: 57 If memory allocation of in pcpu_embed_first_chunk() fails, the allocated memory is not released correctly. In the release loop also the non-allocated elements are released which leads to the following kernel BUG on systems with very little memory: [ 0.000000] kernel BUG at mm/bootmem.c:307! [ 0.000000] illegal operation: 0001 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0 #22 [ 0.000000] task: 0000000000a20ae0 ti: 0000000000a08000 task.ti: 0000000000a08000 [ 0.000000] Krnl PSW : 0400000180000000 0000000000abda7a (__free+0x116/0x154) [ 0.000000] R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3 ... [ 0.000000] [<0000000000abdce2>] mark_bootmem_node+0xde/0xf0 [ 0.000000] [<0000000000abdd9c>] mark_bootmem+0xa8/0x118 [ 0.000000] [<0000000000abcbba>] pcpu_embed_first_chunk+0xe7a/0xf0c [ 0.000000] [<0000000000abcc96>] setup_per_cpu_areas+0x4a/0x28c To fix the problem now only allocated elements are released. This then leads to the correct kernel panic: [ 0.000000] Kernel panic - not syncing: Failed to initialize percpu areas. ... [ 0.000000] Call Trace: [ 0.000000] ([<000000000011307e>] show_trace+0x132/0x150) [ 0.000000] [<0000000000113160>] show_stack+0xc4/0xd4 [ 0.000000] [<00000000007127dc>] dump_stack+0x74/0xd8 [ 0.000000] [<00000000007123fe>] panic+0xea/0x264 [ 0.000000] [<0000000000b14814>] setup_per_cpu_areas+0x5c/0x28c Signed-off-by: Michael Holzheu --- mm/percpu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1705,9 +1705,12 @@ int __init pcpu_embed_first_chunk(size_t goto out_free; out_free_areas: - for (group = 0; group < ai->nr_groups; group++) + for (group = 0; group < ai->nr_groups; group++) { + if (!areas[group]) + continue; free_fn(areas[group], ai->groups[group].nr_units * ai->unit_size); + } out_free: pcpu_free_alloc_info(ai); if (areas) -- 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/