977c7a6d1e
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.