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authorRoland McGrath <roland@redhat.com>2009-02-06 18:15:18 -0800
committerRoland McGrath <roland@redhat.com>2009-02-06 18:22:29 -0800
commitc09249f8d1b84344eca882547afdbffee8c09d14 (patch)
tree9c652c6aaec01f25f15d451b0f0e8009a8a8d530
parent6cec50838ed04a9833fb5549f698d3756bbe7e72 (diff)
x86-64: fix int $0x80 -ENOSYS return
One of my past fixes to this code introduced a different new bug. When using 32-bit "int $0x80" entry for a bogus syscall number, the return value is not correctly set to -ENOSYS. This only happens when neither syscall-audit nor syscall tracing is enabled (i.e., never seen if auditd ever started). Test program: /* gcc -o int80-badsys -m32 -g int80-badsys.c Run on x86-64 kernel. Note to reproduce the bug you need auditd never to have started. */ #include <errno.h> #include <stdio.h> int main (void) { long res; asm ("int $0x80" : "=a" (res) : "0" (99999)); printf ("bad syscall returns %ld\n", res); return res != -ENOSYS; } The fix makes the int $0x80 path match the sysenter and syscall paths. Reported-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Roland McGrath <roland@redhat.com>
-rw-r--r--arch/x86/ia32/ia32entry.S8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 256b00b61892..5a0d76dc56a4 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -418,9 +418,9 @@ ENTRY(ia32_syscall)
orl $TS_COMPAT,TI_status(%r10)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
jnz ia32_tracesys
-ia32_do_syscall:
cmpl $(IA32_NR_syscalls-1),%eax
- ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
+ ja ia32_badsys
+ia32_do_call:
IA32_ARG_FIXUP
call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
ia32_sysret:
@@ -435,7 +435,9 @@ ia32_tracesys:
call syscall_trace_enter
LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
RESTORE_REST
- jmp ia32_do_syscall
+ cmpl $(IA32_NR_syscalls-1),%eax
+ ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
+ jmp ia32_do_call
END(ia32_syscall)
ia32_badsys:

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