From: Thomas Weißschuh thomas.weissschuh@linutronix.de
[ Upstream commit 248ddc80b145515286bfb75d08034ad4c0fdb08e ]
riscv32 does not have any of the older select systemcalls. Use pselect6_time64 instead. poll() is also used to implement sleep().
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Acked-by: Willy Tarreau w@1wt.eu Signed-off-by: Sasha Levin sashal@kernel.org ---
**YES** This commit should be backported to stable kernel trees. Here's my detailed analysis: ## Code Analysis The commit adds support for `pselect6_time64` syscall as a fallback option in the `sys_select()` function in `tools/include/nolibc/sys.h`. The change adds 8 lines of code that implement an additional fallback case: ```c #elif defined(__NR_pselect6_time64) struct __kernel_timespec t; if (timeout) { t.tv_sec = timeout->tv_sec; t.tv_nsec = timeout->tv_usec 0001-Fix- Clippy-warnings.patch 0002-Enhance-inference-prompt-to-utilize- CVEKERNELDIR-whe.patch 0003-Update-to-latest-version-of-clap.patch Cargo.lock Cargo.toml LICENSE README.md analyze_merge_commit.sh io_uring_analysis.txt ksmbd_analysis.txt merge_commit_analysis.txt model prompt src target test_gpio_cleanup.txt test_patch.txt 1000; } return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL); ``` This follows the exact same pattern as the existing `__NR_pselect6` fallback, but uses `__kernel_timespec` instead of `timespec`. ## Why This Should Be Backported **1. Fixes a Real Bug**: RISC-V 32-bit systems that don't provide legacy select syscalls (`__NR_select`, `__NR__newselect`) would fall back to `__NR_pselect6`, but newer systems may only provide `__NR_pselect6_time64`. Without this patch, `select()` calls would fail with `ENOSYS` on such systems. **2. Low Risk**: This is a minimal, targeted fix that: - Only affects systems that lack both legacy select syscalls AND regular pselect6 - Uses an identical code pattern to existing fallbacks - Doesn't modify any existing working code paths - Is self-contained with no dependencies **3. Consistent with Similar Commits**: Looking at the historical reference commits, this follows the same pattern as commit #1 (Status: YES) which added pselect6 support for RISCV, and is much simpler than commits #2-5 (Status: NO) which involved more complex architectural changes. **4. Addresses Platform Compatibility**: The commit message specifically mentions that "riscv32 does not have any of the older select systemcalls" and this provides necessary compatibility for newer RISC-V 32-bit platforms. **5. Minimal Scope**: The change only adds one additional fallback case before the final `ENOSYS` return, making it extremely safe. **6. Essential for Functionality**: Without this fix, basic I/O operations using select() would be broken on affected RISC-V 32-bit systems, making tools/nolibc unusable for such platforms. The commit meets all criteria for stable backporting: it's a clear bugfix, has minimal risk, doesn't introduce new features, and fixes functionality that users depend on.
tools/include/nolibc/sys.h | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 08c1c074bec89..a5decdba40223 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -1023,6 +1023,14 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva t.tv_nsec = timeout->tv_usec * 1000; } return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL); +#elif defined(__NR_pselect6_time64) + struct __kernel_timespec t; + + if (timeout) { + t.tv_sec = timeout->tv_sec; + t.tv_nsec = timeout->tv_usec * 1000; + } + return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL); #else return __nolibc_enosys(__func__, nfds, rfds, wfds, efds, timeout); #endif