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| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2013-09-17 16:57:34 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-09-23 10:51:45 -0400 |
| commit | f851c8d8583891a6e0a447b539db3c39a4f5d43d (patch) | |
| tree | 8f23dc2eaa1dab0475edff66c06b425c17a0304d /mm/percpu.c | |
| parent | 272b98c6455f00884f0350f775c5342358ebb73f (diff) | |
| download | lwn-f851c8d8583891a6e0a447b539db3c39a4f5d43d.tar.gz lwn-f851c8d8583891a6e0a447b539db3c39a4f5d43d.zip | |
percpu: fix bootmem error handling in pcpu_page_first_chunk()
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@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index 8c8e08f3a692..0d10defe951e 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) |