Applied to percpu/for-3.12-fixes with the if conditional flipped. Thanks! ----- 8< ------ >From f851c8d8583891a6e0a447b539db3c39a4f5d43d Mon Sep 17 00:00:00 2001 From: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx> Date: Tue, 17 Sep 2013 16:57:34 +0200 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 tj: Flipped if conditional so that it doesn't need "continue". Signed-off-by: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> --- mm/percpu.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index 8c8e08f..0d10def 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1706,8 +1706,9 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, out_free_areas: for (group = 0; group < ai->nr_groups; group++) - free_fn(areas[group], - ai->groups[group].nr_units * ai->unit_size); + if (areas[group]) + free_fn(areas[group], + ai->groups[group].nr_units * ai->unit_size); out_free: pcpu_free_alloc_info(ai); if (areas) -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>