From 0263aad6fcd84052e2c0f94b9c6c7605f36762e3 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Mon, 25 Jul 2022 11:17:49 +0200 Subject: [PATCH] 5.15-stable patches added patches: sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch --- ...bug_on-condition-for-deboosted-tasks.patch | 45 ++++++++++++++++++ queue-5.15/series | 2 + ...n-is-selected-on-enhanced-ibrs-parts.patch | 46 +++++++++++++++++++ 3 files changed, 93 insertions(+) create mode 100644 queue-5.15/sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch create mode 100644 queue-5.15/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch diff --git a/queue-5.15/sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch b/queue-5.15/sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch new file mode 100644 index 00000000000..2e1997e69ce --- /dev/null +++ b/queue-5.15/sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch @@ -0,0 +1,45 @@ +From ddfc710395cccc61247348df9eb18ea50321cbed Mon Sep 17 00:00:00 2001 +From: Juri Lelli +Date: Thu, 14 Jul 2022 17:19:08 +0200 +Subject: sched/deadline: Fix BUG_ON condition for deboosted tasks + +From: Juri Lelli + +commit ddfc710395cccc61247348df9eb18ea50321cbed upstream. + +Tasks the are being deboosted from SCHED_DEADLINE might enter +enqueue_task_dl() one last time and hit an erroneous BUG_ON condition: +since they are not boosted anymore, the if (is_dl_boosted()) branch is +not taken, but the else if (!dl_prio) is and inside this one we +BUG_ON(!is_dl_boosted), which is of course false (BUG_ON triggered) +otherwise we had entered the if branch above. Long story short, the +current condition doesn't make sense and always leads to triggering of a +BUG. + +Fix this by only checking enqueue flags, properly: ENQUEUE_REPLENISH has +to be present, but additional flags are not a problem. + +Fixes: 64be6f1f5f71 ("sched/deadline: Don't replenish from a !SCHED_DEADLINE entity") +Signed-off-by: Juri Lelli +Signed-off-by: Peter Zijlstra (Intel) +Cc: stable@vger.kernel.org +Link: https://lkml.kernel.org/r/20220714151908.533052-1-juri.lelli@redhat.com +Signed-off-by: Greg Kroah-Hartman +--- + kernel/sched/deadline.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +--- a/kernel/sched/deadline.c ++++ b/kernel/sched/deadline.c +@@ -1561,7 +1561,10 @@ static void enqueue_task_dl(struct rq *r + * the throttle. + */ + p->dl.dl_throttled = 0; +- BUG_ON(!is_dl_boosted(&p->dl) || flags != ENQUEUE_REPLENISH); ++ if (!(flags & ENQUEUE_REPLENISH)) ++ printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n", ++ task_pid_nr(p)); ++ + return; + } + diff --git a/queue-5.15/series b/queue-5.15/series index e48d96a71e8..756d57442f1 100644 --- a/queue-5.15/series +++ b/queue-5.15/series @@ -134,3 +134,5 @@ spi-bcm2835-bcm2835_spi_handle_err-fix-null-pointer-deref-for-non-dma-transfers. kvm-don-t-null-dereference-ops-destroy.patch mm-mempolicy-fix-uninit-value-in-mpol_rebind_policy.patch bpf-make-sure-mac_header-was-set-before-using-it.patch +sched-deadline-fix-bug_on-condition-for-deboosted-tasks.patch +x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch diff --git a/queue-5.15/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch b/queue-5.15/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch new file mode 100644 index 00000000000..90c102d600d --- /dev/null +++ b/queue-5.15/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch @@ -0,0 +1,46 @@ +From eb23b5ef9131e6d65011de349a4d25ef1b3d4314 Mon Sep 17 00:00:00 2001 +From: Pawan Gupta +Date: Thu, 14 Jul 2022 16:15:35 -0700 +Subject: x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts + +From: Pawan Gupta + +commit eb23b5ef9131e6d65011de349a4d25ef1b3d4314 upstream. + +IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at +every kernel entry/exit. On Enhanced IBRS parts setting +MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at +every kernel entry/exit incur unnecessary performance loss. + +When Enhanced IBRS feature is present, print a warning about this +unnecessary performance loss. + +Signed-off-by: Pawan Gupta +Signed-off-by: Peter Zijlstra (Intel) +Reviewed-by: Thadeu Lima de Souza Cascardo +Cc: stable@vger.kernel.org +Link: https://lore.kernel.org/r/2a5eaf54583c2bfe0edc4fea64006656256cca17.1657814857.git.pawan.kumar.gupta@linux.intel.com +Signed-off-by: Greg Kroah-Hartman +--- + arch/x86/kernel/cpu/bugs.c | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/arch/x86/kernel/cpu/bugs.c ++++ b/arch/x86/kernel/cpu/bugs.c +@@ -968,6 +968,7 @@ static inline const char *spectre_v2_mod + #define SPECTRE_V2_LFENCE_MSG "WARNING: LFENCE mitigation is not recommended for this CPU, data leaks possible!\n" + #define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n" + #define SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS+LFENCE mitigation and SMT, data leaks possible via Spectre v2 BHB attacks!\n" ++#define SPECTRE_V2_IBRS_PERF_MSG "WARNING: IBRS mitigation selected on Enhanced IBRS CPU, this may cause unnecessary performance loss\n" + + #ifdef CONFIG_BPF_SYSCALL + void unpriv_ebpf_notify(int new_state) +@@ -1408,6 +1409,8 @@ static void __init spectre_v2_select_mit + + case SPECTRE_V2_IBRS: + setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS); ++ if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) ++ pr_warn(SPECTRE_V2_IBRS_PERF_MSG); + break; + + case SPECTRE_V2_LFENCE: -- 2.47.3