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author | Daniel Bristot de Oliveira <bristot@redhat.com> | 2014-07-22 23:27:41 -0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2014-07-28 10:00:08 +0200 |
commit | d8d28c8f00e84a72e8bee39a85835635417bee49 (patch) | |
tree | d3c0778a56f5e9cdbb90fd47f1dd36625c6e705f /mm | |
parent | 64aa90f26c06e1cb2aacfb98a7d0eccfbd6c1a91 (diff) | |
download | op-kernel-dev-d8d28c8f00e84a72e8bee39a85835635417bee49.zip op-kernel-dev-d8d28c8f00e84a72e8bee39a85835635417bee49.tar.gz |
sched: Fix sched_setparam() policy == -1 logic
The scheduler uses policy == -1 to preserve the current policy state to
implement sched_setparam(). But, as (int) -1 is equals to 0xffffffff,
it's matching the if (policy & SCHED_RESET_ON_FORK) on
_sched_setscheduler(). This match changes the policy value to an
invalid value, breaking the sched_setparam() syscall.
This patch checks policy == -1 before check the SCHED_RESET_ON_FORK flag.
The following program shows the bug:
int main(void)
{
struct sched_param param = {
.sched_priority = 5,
};
sched_setscheduler(0, SCHED_FIFO, ¶m);
param.sched_priority = 1;
sched_setparam(0, ¶m);
param.sched_priority = 0;
sched_getparam(0, ¶m);
if (param.sched_priority != 1)
printf("failed priority setting (found %d instead of 1)\n",
param.sched_priority);
else
printf("priority setting fine\n");
}
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org> # 3.14+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Fixes: 7479f3c9cf67 "sched: Move SCHED_RESET_ON_FORK into attr::sched_flags"
Link: http://lkml.kernel.org/r/9ebe0566a08dbbb3999759d3f20d6004bb2dbcfa.1406079891.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions