From: Gang Ba <Gang.Ba@amd.com>
Date: Tue, 14 Jul 2026 19:08:57 +0000 (-0400)
Subject: drm/amdkfd: Fix missing authorization check in KFD_IOC_DBG_TRAP_DISABLE
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=99b2fe4f19e3be0a8d0a0b5ea98d855970889653;p=thirdparty%2Flinux.git

drm/amdkfd: Fix missing authorization check in KFD_IOC_DBG_TRAP_DISABLE

Prevent unauthorized termination of active GPU debug sessions.
Previously, users with /dev/kfd access could terminate another process's
debug session without proper ownership or ptrace authorization.

Signed-off-by: Gang Ba <Gang.Ba@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 4db4c5ffd5585b72622ecf6ffedf2da258ee23f5)
Cc: stable@vger.kernel.org
---

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index c7edebd2fd8a..e1689b3d2add 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -3109,10 +3109,14 @@ static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process *p, v
 		goto out;
 	}
 
-	/* Check if target is still PTRACED. */
+	/*
+	 * Verify debugger has permission to debug target process.
+	 * For cross-process debugging, require active ptrace relationship.
+	 * This applies to ALL operations to prevent unauthorized interference.
+	 */
 	rcu_read_lock();
-	if (target != p && args->op != KFD_IOC_DBG_TRAP_DISABLE
-				&& ptrace_parent(target->lead_thread) != current) {
+	if (target != p && ptrace_parent(target->lead_thread) != current
+			&& target->debugger_process != p) {
 		pr_err("PID %i is not PTRACED and cannot be debugged\n", args->pid);
 		r = -EPERM;
 	}