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| author |   Daniel Henrique Barboza <danielhb413@gmail.com> | 2022-02-24 15:23:12 -0300 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-03-01 23:41:01 +1100 |
| commit | 749ed4a20657bcea66a6e082ca3dc0d228cbec80 (patch) | |
| tree | 176f9a19e4bf1ff4e23179a3f80e1716a2027feb /arch/powerpc/mm/numa.c | |
| parent | powerpc/interrupt: Remove struct interrupt_state (diff) | |
| download | linux-dev-749ed4a20657bcea66a6e082ca3dc0d228cbec80.tar.xz linux-dev-749ed4a20657bcea66a6e082ca3dc0d228cbec80.zip | |
powerpc/mm/numa: skip NUMA_NO_NODE onlining in parse_numa_properties()
Executing node_set_online() when nid = NUMA_NO_NODE results in an
undefined behavior. node_set_online() will call node_set_state(), into
__node_set(), into set_bit(), and since NUMA_NO_NODE is -1 we'll end up
doing a negative shift operation inside
arch/powerpc/include/asm/bitops.h. This potential UB was detected
running a kernel with CONFIG_UBSAN.
The behavior was introduced by commit 10f78fd0dabb ("powerpc/numa: Fix a
regression on memoryless node 0"), where the check for nid > 0 was
removed to fix a problem that was happening with nid = 0, but the result
is that now we're trying to online NUMA_NO_NODE nids as well.
Checking for nid >= 0 will allow node 0 to be onlined while avoiding
this UB with NUMA_NO_NODE.
Fixes: 10f78fd0dabb ("powerpc/numa: Fix a regression on memoryless node 0")
Reported-by: Ping Fang <pifang@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220224182312.1012527-1-danielhb413@gmail.com
Diffstat (limited to 'arch/powerpc/mm/numa.c')
| -rw-r--r-- | arch/powerpc/mm/numa.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index 9d5f710d2c20..b9b7fefbb64b 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -956,7 +956,9 @@ static int __init parse_numa_properties(void) of_node_put(cpu); } - node_set_online(nid); + /* node_set_online() is an UB if 'nid' is negative */ + if (likely(nid >= 0)) + node_set_online(nid); } get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells); |