dm-stats: fix a crash if allocation of per-cpu data fails

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If "dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu))" fails, the code
jumps to the "out" label and calls dm_stat_free. dm_stat_free does
"for_each_possible_cpu(cpu) { dm_kvfree(s->stat_percpu[cpu][0].histogram,
s->histogram_alloc_size);", which crashes with NULL pointer dereference
if s->stat_percpu[cpu] is NULL.

This commit fixes the bug by testing s->stat_percpu[cpu] for NULL before
using it.

Reported-by: Junzhe Yu <junzheyu1@gmail.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: fd2ed4d252 ("dm: add statistics support")
Cc: stable@vger.kernel.org

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This commit is contained in:

Mikulas Patocka 2026-08-03 23:34:02 +02:00

parent 4538a287bd

commit cc87e26d9c

1 changed files with 4 additions and 2 deletions

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drivers/md/dm-stats.c

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