When 32-bit userspace application is running on 64-bit kernel, the 32-bit syscall return code would be changed from u32 to u64 in regs_return_value and then changed to s64. Hence the negative return code would be treated as a positive number and results in a non-error in, for example, audit like below.
type=SYSCALL msg=audit(1611110715.887:582): arch=40000028 syscall=322 success=yes exit=4294967283 This patch forces the u32->s32->s64 for compat tasks. Signed-off-by: He Zhe <zhe...@windriver.com> --- include/linux/ptrace.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index b5ebf6c01292..bc3056fff8a6 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -260,7 +260,9 @@ static inline void ptrace_release_task(struct task_struct *task) * is an error value. On some systems like ia64 and powerpc they have different * indicators of success/failure and must define their own. */ -#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs)))) +#define is_syscall_success(regs) (!IS_ERR_VALUE(is_compat_task() ? \ + (unsigned long)(s64)(s32)(regs_return_value(regs)) : \ + (unsigned long)(regs_return_value(regs)))) #endif /* -- 2.17.1
