diff options
| author | Christian Krinitsin <mail@krinitsin.com> | 2025-07-03 07:27:52 +0000 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-07-03 07:27:52 +0000 |
| commit | d0c85e36e4de67af628d54e9ab577cc3fad7796a (patch) | |
| tree | f8f784b0f04343b90516a338d6df81df3a85dfa2 /results/classifier/gemma3:12b/kernel/1824344 | |
| parent | 7f4364274750eb8cb39a3e7493132fca1c01232e (diff) | |
| download | emulator-bug-study-d0c85e36e4de67af628d54e9ab577cc3fad7796a.tar.gz emulator-bug-study-d0c85e36e4de67af628d54e9ab577cc3fad7796a.zip | |
add deepseek and gemma results
Diffstat (limited to 'results/classifier/gemma3:12b/kernel/1824344')
| -rw-r--r-- | results/classifier/gemma3:12b/kernel/1824344 | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/kernel/1824344 b/results/classifier/gemma3:12b/kernel/1824344 new file mode 100644 index 00000000..438a32dd --- /dev/null +++ b/results/classifier/gemma3:12b/kernel/1824344 @@ -0,0 +1,46 @@ + +x86: retf or iret pagefault sets wrong error code + +With a x86_64 or i386 guest, non-KVM, when trying to execute a +"iret/iretq/retf" instruction in userspace with invalid stack pointer +(under a protected mode OS, like Linux), wrong bits are set in the +pushed error code; bit 2 is not set, indicating the error comes from +kernel space. + +If the guest OS is using this flag to decide whether this was a kernel +or user page fault, it will mistakenly decide a kernel has irrecoverably +faulted, possibly causing guest OS panic. + + +How to reproduce the problem a guest (non-KVM) Linux: +Note, on recent Linux kernel version, this needs a CPU with SMAP support +(eg. -cpu max) + +$ cat tst.c +int main() +{ +__asm__ volatile ( +"mov $0,%esp\n" +"retf" +); +return 0; +} + +$ gcc tst.c +$ ./a.out +Killed + + +"dmesg" shows the kernel has in fact triggered a "BUG: unable to handle +kernel NULL pointer dereference...", but it has "recovered" by killing +the faulting process (see attached screenshot). + + +Using self-compiled qemu from git: +commit 532cc6da74ec25b5ba6893b5757c977d54582949 (HEAD -> master, tag: v4.0.0-rc3, origin/master, origin/HEAD) +Author: Peter Maydell <email address hidden> +Date: Wed Apr 10 15:38:59 2019 +0100 + + Update version for v4.0.0-rc3 release + + Signed-off-by: Peter Maydell <email address hidden> \ No newline at end of file |