From: Casey Chen Date: Mon, 22 Jul 2024 21:15:48 +0000 (-0600) Subject: perf tool: fix dereferencing NULL al->maps X-Git-Tag: nvme-6.12-2024-10-18~27^2~42^2~6 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4c17736689ccfc44ec7dcc472577f25c34cf8724;p=nvme.git perf tool: fix dereferencing NULL al->maps With 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions"), when cpumode is 3 (macro PERF_RECORD_MISC_HYPERVISOR), thread__find_map() could return with al->maps being NULL. The path below could add a callchain_cursor_node with NULL ms.maps. add_callchain_ip() thread__find_symbol(.., &al) thread__find_map(.., &al) // al->maps becomes NULL ms.maps = maps__get(al.maps) callchain_cursor_append(..., &ms, ...) node->ms.maps = maps__get(ms->maps) Then the path below would dereference NULL maps and get segfault. fill_callchain_info() maps__machine(node->ms.maps); Fix it by checking if maps is NULL in fill_callchain_info(). Fixes: 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions") Signed-off-by: Casey Chen Reviewed-by: Ian Rogers Reviewed-by: Arnaldo Carvalho de Melo Acked-by: Namhyung Kim Cc: yzhong@purestorage.com Link: https://lore.kernel.org/r/20240722211548.61455-1-cachen@purestorage.com Signed-off-by: Namhyung Kim --- diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c index 1730b852a947..6d075648d2cc 100644 --- a/tools/perf/util/callchain.c +++ b/tools/perf/util/callchain.c @@ -1141,7 +1141,7 @@ int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *samp int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node, bool hide_unresolved) { - struct machine *machine = maps__machine(node->ms.maps); + struct machine *machine = node->ms.maps ? maps__machine(node->ms.maps) : NULL; maps__put(al->maps); al->maps = maps__get(node->ms.maps);