x86: ia32 ptrace vs -ENOSYS
When we're stopped at syscall entry tracing, ptrace can change the %eax value from -ENOSYS to something else. If no system call is actually made because the syscall number (now in orig_eax) is bad, then the %eax value set by ptrace should be returned to the user. But, instead it gets reset to -ENOSYS again. This is a regression from the native 32-bit kernel. This change fixes it by leaving the return value alone after entry tracing. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -325,7 +325,7 @@ ENTRY(ia32_syscall)
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jnz ia32_tracesys
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ia32_do_syscall:
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cmpl $(IA32_NR_syscalls-1),%eax
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ja ia32_badsys
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ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
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IA32_ARG_FIXUP
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call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
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ia32_sysret:
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@ -335,7 +335,7 @@ ia32_sysret:
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ia32_tracesys:
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SAVE_REST
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CLEAR_RREGS
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movq $-ENOSYS,RAX(%rsp) /* really needed? */
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movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
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movq %rsp,%rdi /* &pt_regs -> arg1 */
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call syscall_trace_enter
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LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
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