From 975776841e689dd8ba36df9fa72ac3eca3c2957a Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 30 Mar 2025 15:49:55 +0200 Subject: sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP kernel/sched/isolation.c obviously makes no sense without CONFIG_SMP, but the Kconfig entry we have right now: config CPU_ISOLATION bool "CPU isolation" depends on SMP || COMPILE_TEST allows the creation of pointless .config's which cause build failures. Reported-by: kernel test robot Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250330134955.GA7910@redhat.com Closes: https://lore.kernel.org/oe-kbuild-all/202503260646.lrUqD3j5-lkp@intel.com/ --- init/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 681f38ee68db..ab9b0c2c3d52 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -709,7 +709,7 @@ endmenu # "CPU/Task time and stats accounting" config CPU_ISOLATION bool "CPU isolation" - depends on SMP || COMPILE_TEST + depends on SMP default y help Make sure that CPUs running critical tasks are not disturbed by -- cgit v1.2.3 From 169eae7711ea4b745e2d33d53e7b88689b10e1a0 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 27 Mar 2025 09:29:45 -0400 Subject: rseq: Eliminate useless task_work on execve Eliminate a useless task_work on execve by moving the call to rseq_set_notify_resume() from sched_mm_cid_after_execve() to the error path of bprm_execve(). The call to rseq_set_notify_resume() from sched_mm_cid_after_execve() is pointless in the success case, because rseq_execve() will clear the rseq pointer before returning to userspace. sched_mm_cid_after_execve() is called from both the success and error paths of bprm_execve(). The call to rseq_set_notify_resume() is needed on error because the mm_cid may have changed. Also move the rseq_execve() to right after sched_mm_cid_after_execve() in bprm_execve(). [ mingo: Merged to a recent upstream kernel, extended the changelog. ] Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar Cc: Oleg Nesterov Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250327132945.1558783-1-mathieu.desnoyers@efficios.com --- fs/exec.c | 3 ++- kernel/sched/core.c | 1 - 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 5d1c0d2dc403..8e4ea5f1e64c 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1864,9 +1864,9 @@ static int bprm_execve(struct linux_binprm *bprm) goto out; sched_mm_cid_after_execve(current); + rseq_execve(current); /* execve succeeded */ current->in_execve = 0; - rseq_execve(current); user_events_execve(current); acct_update_integrals(current); task_numa_free(current, false); @@ -1883,6 +1883,7 @@ out: force_fatal_sig(SIGSEGV); sched_mm_cid_after_execve(current); + rseq_set_notify_resume(current); current->in_execve = 0; return retval; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cfaca3040b2f..c81cf642dba0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -10703,7 +10703,6 @@ void sched_mm_cid_after_execve(struct task_struct *t) smp_mb(); t->last_mm_cid = t->mm_cid = mm_cid_get(rq, t, mm); } - rseq_set_notify_resume(t); } void sched_mm_cid_fork(struct task_struct *t) -- cgit v1.2.3