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[1/2] target/i386: Make sure that vsyscall's tb->size != 0

Message ID 20210512040250.203953-2-iii@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series target/i386: Make sure that vsyscall's tb->size != 0 | expand

Commit Message

Ilya Leoshkevich May 12, 2021, 4:02 a.m. UTC 
tb_gen_code() assumes that tb->size must never be zero, otherwise it
may produce spurious exceptions. For x86_64 this may happen when
creating a translation block for the vsyscall page.

Fix by pretending that vsyscall translation blocks have at least one
instruction.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 target/i386/tcg/translate.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Richard Henderson May 14, 2021, 2:30 p.m. UTC | #1 
On 5/11/21 11:02 PM, Ilya Leoshkevich wrote:
> tb_gen_code() assumes that tb->size must never be zero, otherwise it
> may produce spurious exceptions. For x86_64 this may happen when
> creating a translation block for the vsyscall page.
> 
> Fix by pretending that vsyscall translation blocks have at least one
> instruction.
> 
> Signed-off-by: Ilya Leoshkevich<iii@linux.ibm.com>
> ---
>   target/i386/tcg/translate.c | 1 +
>   1 file changed, 1 insertion(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 880bc45561..b5a2b981e2 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -8572,6 +8572,7 @@  static void i386_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
      */
     if ((dc->base.pc_next & TARGET_PAGE_MASK) == TARGET_VSYSCALL_PAGE) {
         gen_exception(dc, EXCP_VSYSCALL, dc->base.pc_next);
+        dc->base.pc_next = dc->pc + 1;
         return;
     }
 #endif