Re: [PATCH 1/7] x86/vdso: Respect COMPAT_32BIT_TIME
From: "Arnd Bergmann" <arnd@arndb.de>
Date: 2026-03-03 21:27:52
Also in:
linux-arm-kernel, linux-mips, lkml
On Tue, Mar 3, 2026, at 22:00, H. Peter Anvin wrote:
On March 3, 2026 12:50:33 PM PST, Arnd Bergmann [off-list ref] wrote:quoted
On Tue, Mar 3, 2026, at 19:11, H. Peter Anvin wrote:quoted
A bigger question is whether or not we should omit these from the vDSO completely (potentially causing link failures) or replace them with stubs returning -ENOSYS.I see no harm in keeping gettimeofday() in the vdso when COMPAT_32BIT_TIME is turned on, as existing code will call it no matter whether it's in the vdso or the syscall.That wasn't the point. The point was what kind of error behavior we want.
I see. I would argue here that a link failure is actually the best
case then: the entire point of CONFIG_COMPAT_32BIT_TIME=n is to
enforce the fail-early case, as opposed to silent data corruption
after (now) 12 years of operation.
I don't think there is an actual link failure here, as dl_vdso_vsym()
resolves it at runtime by glibc (when using time32), while musl
doesn't use __vdso_gettimeofday at all.
Arnd