Hi Markus,
On 8/8/25 10:08, Markus Armbruster wrote:
tcg_region_init() calls one of qemu_mprotect_rwx(),
qemu_mprotect_rw(), and mprotect(), then reports failure with
error_setg_errno(&error_fatal, errno, ...).
The use of &error_fatal is undesirable. qapi/error.h advises:
* Please don't error_setg(&error_fatal, ...), use error_report() and
* exit(), because that's more obvious.
The use of errno is wrong. qemu_mprotect_rwx() and qemu_mprotect_rw()
wrap around qemu_mprotect__osdep(). qemu_mprotect__osdep() calls
mprotect() on POSIX, VirtualProtect() on Windows, and reports failure
with error_report(). VirtualProtect() doesn't set errno. mprotect()
does, but error_report() may clobber it.
Fix tcg_region_init() to report errors only when it calls mprotect(),
and rely on qemu_mprotect_rwx()'s and qemu_mprotect_rw()'s error
reporting otherwise. Use error_report(), not error_setg().
Fixes: 22c6a9938f75 (tcg: Merge buffer protection and guard page protection)
Fixes: 6bc144237a85 (tcg: Use Error with alloc_code_gen_buffer)
Cc: Richard Henderson <richard.hender...@linaro.org>
Signed-off-by: Markus Armbruster <arm...@redhat.com>
---
tcg/region.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tcg/region.c b/tcg/region.c
index 7ea0b37a84..74e3b4b774 100644
--- a/tcg/region.c
+++ b/tcg/region.c
@@ -832,13 +832,17 @@ void tcg_region_init(size_t tb_size, int splitwx,
unsigned max_threads)
} else {
#ifdef CONFIG_POSIX
rc = mprotect(start, end - start, need_prot);
+ if (rc) {
+ error_report("mprotect of jit buffer: %s",
+ strerror(errno));
+ }
+
#else
g_assert_not_reached();
#endif
}
if (rc) {
- error_setg_errno(&error_fatal, errno,
- "mprotect of jit buffer");
+ exit(1);
- Before:
Error displayed when qemu_mprotect_rwx/qemu_mprotect_rw/mprotect fail,
then exit.
- After:
Error only displayed when mprotect() fails, then exit.
Nothing displayed when qemu_mprotect_rwx() or qemu_mprotect_rw() failed,
and exit.
Can we keep the "mprotect of jit buffer" string displayed before
exiting, but using error_report()?
}
}
if (have_prot != 0) {
