diff options
author | Li Zefan <lizf@cn.fujitsu.com> | 2009-03-27 10:20:09 +0800 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-03-31 17:27:45 +0200 |
commit | 17ba97e347bec9bbc47a0877c7a098708982129d (patch) | |
tree | b6a7472c354e4135f1ea47482d19ae277be65dee /.mailmap | |
parent | 35ac51bfe4c293b67ce9f85082ba0b9bc6123c40 (diff) |
blktrace: fix blk_probes_ref chaos
Impact: fix mixed ioctl and ftrace-plugin blktrace use refcount bugs
ioctl-based blktrace allocates bt and registers tracepoints when
ioctl(BLKTRACESETUP), and do all cleanups when ioctl(BLKTRACETEARDOWN).
while ftrace-based blktrace allocates/frees bt when:
# echo 1/0 > /sys/block/sda/sda1/trace/enable
and registers/unregisters tracepoints when:
# echo blk/nop > /debugfs/tracing/current_tracer
or
# echo 1/0 > /debugfs/tracing/tracing_enable
The separatation of allocation and registeration causes 2 problems:
1. current user-space blktrace still calls ioctl(TEARDOWN) when
ioctl(SETUP) failed:
# echo 1 > /sys/block/sda/sda1/trace/enable
# blktrace /dev/sda
BLKTRACESETUP: Device or resource busy
^C
and now blk_probes_ref == -1
2. Another way to make blk_probes_ref == -1:
# plugin sdb && mount sdb1
# echo 1 > /sys/block/sdb/sdb1/trace/enable
# remove sdb
This patch does the allocation and registeration when writing
sdaX/trace/enable.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to '.mailmap')
0 files changed, 0 insertions, 0 deletions