Commit 977c7a6d authored Feb 28, 2019 by Wei Li Committed by Arnaldo Carvalho de Melo Mar 28, 2019

perf machine: Update kernel map address and re-order properly



Since commit 1fb87b8e ("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 ee05d217 ("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>

parent 707c373c

tools/perf/util/machine.c

+20 −12

Original line number	Diff line number	Diff line
		@@ -1421,6 +1421,20 @@ 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);
		@@ -1453,17 +1467,11 @@ 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))
		@@ -1599,7 +1607,7 @@ 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);

		/*

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