| Message ID | 20240801134549.91291-2-roxana.nicolescu@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix virtualbox regression | expand |
diff --git a/include/linux/randomize_kstack.h b/include/linux/randomize_kstack.h index 5d52d15faee0c..d373f1bcbf7ca 100644 --- a/include/linux/randomize_kstack.h +++ b/include/linux/randomize_kstack.h @@ -58,7 +58,7 @@ DECLARE_PER_CPU(u32, kstack_offset); if (static_branch_maybe(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT, \ &randomize_kstack_offset)) { \ u32 offset = raw_cpu_read(kstack_offset); \ - offset = ror32(offset, 5) ^ (rand); \ + offset ^= (rand); \ raw_cpu_write(kstack_offset, offset); \ } \ } while (0)
BugLink: https://bugs.launchpad.net/bugs/2073267 This reverts "randomize_kstack: Improve entropy diffusion" that changed the kernel stack for entropy to 1KiB, limitting the thread kernel stack to 15KiB. This impacts virtualbox 6.1.50 on jammy, that is no longer maintained upstream. The issue does not persist on version 7.0.20 due to a code refactoring that probably resulted in less stack usage. Fixing it on the jammy virtualbox package side is not straightfoward because the fix is not easy to backport to 6.x and upgrading the jammy package to 7.x breaks current users machines. This is a temporary solution needed due to the impact, more investigation is required. Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com> --- include/linux/randomize_kstack.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)