| Message ID | 20220224182312.1012527-1-danielhb413@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | powerpc/mm/numa: skip NUMA_NO_NODE onlining in parse_numa_properties() | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 24 jobs. |
| snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
| snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 7 jobs. |
On Thu, 24 Feb 2022 15:23:12 -0300, Daniel Henrique Barboza wrote: > 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. > > [...] Applied to powerpc/next. [1/1] powerpc/mm/numa: skip NUMA_NO_NODE onlining in parse_numa_properties() https://git.kernel.org/powerpc/c/749ed4a20657bcea66a6e082ca3dc0d228cbec80 cheers
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);
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. Reported-by: Ping Fang <pifang@redhat.com> Cc: Diego Domingos <diegodo@linux.vnet.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Fixes: 10f78fd0dabb ("powerpc/numa: Fix a regression on memoryless node 0") Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- arch/powerpc/mm/numa.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)