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author | Frank Li <Frank.Li@nxp.com> | 2019-01-11 11:56:47 -0600 |
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committer | Nathan Hjelm <hjelmn@me.com> | 2019-01-30 22:38:32 -0700 |
commit | c20bb681db3fd2d80cbca4477eaf0d3a502ed4c6 (patch) | |
tree | a0b84b7871c47f54d686bfbba6cc7acf90f5f9a8 /libusb/libusb.h | |
parent | 91a49831f3b05f6739c4af21aa6ff802cfe3ac71 (diff) | |
download | libusb-c20bb681db3fd2d80cbca4477eaf0d3a502ed4c6.tar.gz |
fix race condition at event_handles
event_handles supposed just run at a thread.
There are re-entry check at begin.
1: if (usbi_handling_events(ctx))
2: return LIBUSB_ERROR_BUSY;
3: usbi_stat_event_handle(ctx);
this code is hold any lock
it is possible two thread check 1 at the same time, then
go through to 3. So two threads will run event_handles.
above 3 line code should hold event_data_lock to avoid above
race condition.
1: usbi_mutex_lock($ctx->event_data_lock);
2: r = 0;
3: if (usbi_handling_events(ctx))
4: r = LIBUSB_ERROR_BUSY;
5: else
6: usbi_start_event_handling(ctx);
7: usbi_mutex_unlock($ctx->event_data_lock);
8: if(r)
9: return r;
check and set in an atomic operations.
Closes #520
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Nathan Hjelm <hjelmn@me.com>
Diffstat (limited to 'libusb/libusb.h')
0 files changed, 0 insertions, 0 deletions