Re: Linux 6.6.139

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

diff --git a/Makefile b/Makefile
index 7878fd783212..d00b00f0c54f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 6
-SUBLEVEL = 138
+SUBLEVEL = 139
 EXTRAVERSION =
 NAME = Pinguïn Aangedreven
 
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index deb5fe001776..c9f83af0e0b7 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -675,6 +675,7 @@
 /* Zen4 */
 #define MSR_ZEN4_BP_CFG			0xc001102e
 #define MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT 5
+#define MSR_ZEN2_BP_CFG_BUG_FIX_BIT	33
 
 /* Zen 2 */
 #define MSR_ZEN2_SPECTRAL_CHICKEN	0xc00110e3
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 211141d37d15..c5bcf4384830 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1166,6 +1166,9 @@ static void init_amd_zen2(struct cpuinfo_x86 *c)
 		msr_clear_bit(MSR_AMD64_CPUID_FN_7, 18);
 		pr_emerg("RDSEED is not reliable on this platform; disabling.\n");
 	}
+
+	if (!cpu_has(c, X86_FEATURE_HYPERVISOR))
+		msr_set_bit(MSR_ZEN4_BP_CFG, MSR_ZEN2_BP_CFG_BUG_FIX_BIT);
 }
 
 static void init_amd_zen3(struct cpuinfo_x86 *c)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9c7c67efce34..856a560100c2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -916,6 +916,9 @@ struct task_struct {
 	 */
 	unsigned			sched_remote_wakeup:1;
 
+	/* Save user-dumpable when mm goes away */
+	unsigned			user_dumpable:1;
+
 	/* Bit to tell LSMs we're in execve(): */
 	unsigned			in_execve:1;
 	unsigned			in_iowait:1;
diff --git a/kernel/exit.c b/kernel/exit.c
index 03a1dd32e6ff..686bbe72bb41 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -559,6 +559,7 @@ static void exit_mm(void)
 	 */
 	smp_mb__after_spinlock();
 	local_irq_disable();
+	current->user_dumpable = (get_dumpable(mm) == SUID_DUMP_USER);
 	current->mm = NULL;
 	membarrier_update_current_mm(NULL);
 	enter_lazy_tlb(mm, current);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 443057bee87c..3c7d122a37fb 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -283,11 +283,24 @@ static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
 	return ns_capable(ns, CAP_SYS_PTRACE);
 }
 
+static bool task_still_dumpable(struct task_struct *task, unsigned int mode)
+{
+	struct mm_struct *mm = task->mm;
+	if (mm) {
+		if (get_dumpable(mm) == SUID_DUMP_USER)
+			return true;
+		return ptrace_has_cap(mm->user_ns, mode);
+	}
+
+	if (task->user_dumpable)
+		return true;
+	return ptrace_has_cap(&init_user_ns, mode);
+}
+
 /* Returns 0 on success, -errno on denial. */
 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 {
 	const struct cred *cred = current_cred(), *tcred;
-	struct mm_struct *mm;
 	kuid_t caller_uid;
 	kgid_t caller_gid;
 
@@ -348,11 +361,8 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 	 * Pairs with a write barrier in commit_creds().
 	 */
 	smp_rmb();
-	mm = task->mm;
-	if (mm &&
-	    ((get_dumpable(mm) != SUID_DUMP_USER) &&
-	     !ptrace_has_cap(mm->user_ns, mode)))
-	    return -EPERM;
+	if (!task_still_dumpable(task, mode))
+		return -EPERM;
 
 	return security_ptrace_access_check(task, mode);
 }
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index 76f9cad9fb62..d108bc6634ed 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -638,6 +638,9 @@
 /* AMD Last Branch Record MSRs */
 #define MSR_AMD64_LBR_SELECT			0xc000010e
 
+#define MSR_ZEN4_BP_CFG			0xc001102e
+#define MSR_ZEN2_BP_CFG_BUG_FIX_BIT	33
+
 /* Fam 17h MSRs */
 #define MSR_F17H_IRPERF			0xc00000e9