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-rw-r--r--arch/x86/kernel/traps.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 32b2d39272e0..e19df6cde35d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -937,10 +937,13 @@ static __always_inline void exc_debug_user(struct pt_regs *regs,
instrumentation_begin();
/*
- * Clear the virtual DR6 value, ptrace() routines will set bits here
- * for things it wants signals for.
+ * Start the virtual/ptrace DR6 value with just the DR_STEP mask
+ * of the real DR6. ptrace_triggered() will set the DR_TRAPn bits.
+ *
+ * Userspace expects DR_STEP to be visible in ptrace_get_debugreg(6)
+ * even if it is not the result of PTRACE_SINGLESTEP.
*/
- current->thread.virtual_dr6 = 0;
+ current->thread.virtual_dr6 = (dr6 & DR_STEP);
/*
* The SDM says "The processor clears the BTF flag when it

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