On Tue Apr 14, 2026 at 4:36 PM CEST, Alexei Starovoitov wrote: > On Tue, Apr 14, 2026 at 6:13 AM Alexis Lothoré > <[email protected]> wrote: >> >> Hi Andrey, thanks for the prompt review ! >> >> On Tue Apr 14, 2026 at 12:19 AM CEST, Andrey Konovalov wrote: >> > On Mon, Apr 13, 2026 at 8:29 PM Alexis Lothoré (eBPF Foundation) >> > <[email protected]> wrote: >> >> >> >> [...] >> >> >> +#ifdef CONFIG_KASAN_GENERIC >> >> +void __asan_load1(void *p); >> >> +void __asan_store1(void *p); >> >> +void __asan_load2(void *p); >> >> +void __asan_store2(void *p); >> >> +void __asan_load4(void *p); >> >> +void __asan_store4(void *p); >> >> +void __asan_load8(void *p); >> >> +void __asan_store8(void *p); >> >> +void __asan_load16(void *p); >> >> +void __asan_store16(void *p); >> >> +#endif /* CONFIG_KASAN_GENERIC */ >> > >> > This looks ugly, let's not do this unless it's really required. >> > >> > You can just use kasan_check_read/write() instead - these are public >> > wrappers around the same shadow memory checking functions. And they >> > also work with the SW_TAGS mode, in case the BPF would want to use >> > that mode at some point. (For HW_TAGS, we only have kasan_check_byte() >> > that checks a single byte, but it can be extended in the future if >> > required to be used by BPF.) >> >> ACK, I'll try to use those kasan_check_read and kasan_check_write rather >> than __asan_{load,store}X. > > No. The performance penalty will be too high.
Since we are mentioning it, I did not consider yet any performance comparision/benchmarking (and I am not really familiar with usual bpf performance validation practices for new bpf features). Is there any existing test I should take a look at for this ? Maybe some specific benches in tools/testing/selftests/bpf/bench ? > hw_tags won't work without corresponding JIT work. > I see no point sacrificing performance for aesthetics. > __asan_load/storeX is what compilers emit. > In that sense JIT is a compiler it should emit exactly the same. -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
