From: Wei Li liwei391@huawei.com
[ Upstream commit 977c7a6d1e263ff1d755f28595b99e4bc0c48a9f ]
Since commit 1fb87b8e9599 ("perf machine: Don't search for active kernel start in __machine__create_kernel_maps"), the __machine__create_kernel_maps() just create a map what start and end are both zero. Though the address will be updated later, the order of map in the rbtree may be incorrect.
The commit ee05d21791db ("perf machine: Set main kernel end address properly") fixed the logic in machine__create_kernel_maps(), but it's still wrong in function machine__process_kernel_mmap_event().
To reproduce this issue, we need an environment which the module address is before the kernel text segment. I tested it on an aarch64 machine with kernel 4.19.25:
[root@localhost hulk]# grep _stext /proc/kallsyms ffff000008081000 T _stext [root@localhost hulk]# grep _etext /proc/kallsyms ffff000009780000 R _etext [root@localhost hulk]# tail /proc/modules hisi_sas_v2_hw 77824 0 - Live 0xffff00000191d000 nvme_core 126976 7 nvme, Live 0xffff0000018b6000 mdio 20480 1 ixgbe, Live 0xffff0000018ab000 hisi_sas_main 106496 1 hisi_sas_v2_hw, Live 0xffff000001861000 hns_mdio 20480 2 - Live 0xffff000001822000 hnae 28672 3 hns_dsaf,hns_enet_drv, Live 0xffff000001815000 dm_mirror 40960 0 - Live 0xffff000001804000 dm_region_hash 32768 1 dm_mirror, Live 0xffff0000017f5000 dm_log 32768 2 dm_mirror,dm_region_hash, Live 0xffff0000017e7000 dm_mod 315392 17 dm_mirror,dm_log, Live 0xffff000001780000 [root@localhost hulk]#
Before fix:
[root@localhost bin]# perf record sleep 3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.011 MB perf.data (9 samples) ] [root@localhost bin]# perf buildid-list -i perf.data 4c4e46c971ca935f781e603a09b52a92e8bdfee8 [vdso] [root@localhost bin]# perf buildid-list -i perf.data -H 0000000000000000000000000000000000000000 /proc/kcore [root@localhost bin]#
After fix:
[root@localhost tools]# ./perf/perf record sleep 3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.011 MB perf.data (9 samples) ] [root@localhost tools]# ./perf/perf buildid-list -i perf.data 28a6c690262896dbd1b5e1011ed81623e6db0610 [kernel.kallsyms] 106c14ce6e4acea3453e484dc604d66666f08a2f [vdso] [root@localhost tools]# ./perf/perf buildid-list -i perf.data -H 28a6c690262896dbd1b5e1011ed81623e6db0610 /proc/kcore
Signed-off-by: Wei Li liwei391@huawei.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Namhyung Kim namhyung@kernel.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: David Ahern dsahern@gmail.com Cc: Hanjun Guo guohanjun@huawei.com Cc: Kim Phillips kim.phillips@arm.com Cc: Li Bin huawei.libin@huawei.com Cc: Peter Zijlstra peterz@infradead.org Link: http://lkml.kernel.org/r/20190228092003.34071-1-liwei391@huawei.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin (Microsoft) sashal@kernel.org --- tools/perf/util/machine.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 143f7057d581..596db1daee35 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1358,6 +1358,20 @@ static void machine__set_kernel_mmap(struct machine *machine, machine->vmlinux_map->end = ~0ULL; }
+static void machine__update_kernel_mmap(struct machine *machine, + u64 start, u64 end) +{ + struct map *map = machine__kernel_map(machine); + + map__get(map); + map_groups__remove(&machine->kmaps, map); + + machine__set_kernel_mmap(machine, start, end); + + map_groups__insert(&machine->kmaps, map); + map__put(map); +} + int machine__create_kernel_maps(struct machine *machine) { struct dso *kernel = machine__get_kernel(machine); @@ -1390,17 +1404,11 @@ int machine__create_kernel_maps(struct machine *machine) goto out_put; }
- /* we have a real start address now, so re-order the kmaps */ - map = machine__kernel_map(machine); - - map__get(map); - map_groups__remove(&machine->kmaps, map); - - /* assume it's the last in the kmaps */ - machine__set_kernel_mmap(machine, addr, ~0ULL); - - map_groups__insert(&machine->kmaps, map); - map__put(map); + /* + * we have a real start address now, so re-order the kmaps + * assume it's the last in the kmaps + */ + machine__update_kernel_mmap(machine, addr, ~0ULL); }
if (machine__create_extra_kernel_maps(machine, kernel)) @@ -1536,7 +1544,7 @@ static int machine__process_kernel_mmap_event(struct machine *machine, if (strstr(kernel->long_name, "vmlinux")) dso__set_short_name(kernel, "[kernel.vmlinux]", false);
- machine__set_kernel_mmap(machine, event->mmap.start, + machine__update_kernel_mmap(machine, event->mmap.start, event->mmap.start + event->mmap.len);
/*