diff options
Diffstat (limited to 'freed-ora/current/f20/sched-fix-sched_setparam-policy-1-logic.patch')
| -rw-r--r-- | freed-ora/current/f20/sched-fix-sched_setparam-policy-1-logic.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/freed-ora/current/f20/sched-fix-sched_setparam-policy-1-logic.patch b/freed-ora/current/f20/sched-fix-sched_setparam-policy-1-logic.patch new file mode 100644 index 000000000..060e0dcef --- /dev/null +++ b/freed-ora/current/f20/sched-fix-sched_setparam-policy-1-logic.patch @@ -0,0 +1,68 @@ +Bugzilla: 1117942 +Upstream-status: Sent for 3.16 and seen by peterz + +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"); +} + +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Ingo Molnar <mingo@kernel.org> +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: stable@vger.kernel.org # 3.14+ +Fixes: 7479f3c9cf67 "sched: Move SCHED_RESET_ON_FORK into attr::sched_flags" +Reviewed-by: Steven Rostedt <rostedt@goodmis.org> +Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> + +--- + kernel/sched/core.c | 5 +++-- + 1 file changed, 3 insertions(+), 2 deletions(-) + +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index bc1638b..0acf96b 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -3558,9 +3558,10 @@ static int _sched_setscheduler(struct task_struct *p, int policy, + }; + + /* +- * Fixup the legacy SCHED_RESET_ON_FORK hack ++ * Fixup the legacy SCHED_RESET_ON_FORK hack, except if ++ * the policy=-1 was passed by sched_setparam(). + */ +- if (policy & SCHED_RESET_ON_FORK) { ++ if ((policy != -1) && (policy & SCHED_RESET_ON_FORK)) { + attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; + policy &= ~SCHED_RESET_ON_FORK; + attr.sched_policy = policy; +-- +1.9.3 + +-- +To unsubscribe from this list: send the line "unsubscribe linux-kernel" in +the body of a message to majordomo@vger.kernel.org +More majordomo info at http://vger.kernel.org/majordomo-info.html +Please read the FAQ at http://www.tux.org/lkml/ |
