Subject: + mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk.patch added to -mm tree To: holzheu@xxxxxxxxxxxxxxxxxx,cl@xxxxxxxxxxxxxxxxxxxx,tj@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 26 Sep 2013 14:21:22 -0700 The patch titled Subject: mm: fix bootmem error handling in pcpu_page_first_chunk() has been added to the -mm tree. Its filename is mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx> Subject: mm: fix bootmem error handling in pcpu_page_first_chunk() If memory allocation 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 <holzheu@xxxxxxxxxxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/percpu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN mm/percpu.c~mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk mm/percpu.c --- a/mm/percpu.c~mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk +++ a/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) _ Patches currently in -mm which might be from holzheu@xxxxxxxxxxxxxxxxxx are mm-fix-bootmem-error-handling-in-pcpu_page_first_chunk.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html