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Subject[PATCH 1/2] x86-64: syscall-audit: fix 32/64 syscall hole
On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call. A 64-bit process make a 32-bit system call with int $0x80.

In both these cases, audit_syscall_entry() will use the wrong system
call number table and the wrong system call argument registers. This
could be used to circumvent a syscall audit configuration that filters
based on the syscall numbers or argument details.

Signed-off-by: Roland McGrath <>
arch/x86/kernel/ptrace.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 5a4c23d..06ca07f 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1388,7 +1388,7 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
#ifdef CONFIG_X86_32
# define IS_IA32 1
#elif defined CONFIG_IA32_EMULATION
-# define IS_IA32 test_thread_flag(TIF_IA32)
+# define IS_IA32 is_compat_task()
# define IS_IA32 0

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