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path: root/src/runtime/vgetrandom_linux.go
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2025-11-26runtime/secret: implement new secret packageDaniel Morsing
Implement secret.Do. - When secret.Do returns: - Clear stack that is used by the argument function. - Clear all the registers that might contain secrets. - On stack growth in secret mode, clear the old stack. - When objects are allocated in secret mode, mark them and then zero the marked objects immediately when they are freed. - If the argument function panics, raise that panic as if it originated from secret.Do. This removes anything about the secret function from tracebacks. For now, this is only implemented on linux for arm64 and amd64. This is a rebased version of Keith Randalls initial implementation at CL 600635. I have added arm64 support, signal handling, preemption handling and dealt with vDSOs spilling into system stacks. Fixes #21865 Change-Id: I6fbd5a233beeaceb160785e0c0199a5c94d8e520 Co-authored-by: Keith Randall <khr@golang.org> Reviewed-on: https://go-review.googlesource.com/c/go/+/704615 Reviewed-by: Roland Shoemaker <roland@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Filippo Valsorda <filippo@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2025-05-29runtime: add vgetrandom lock rankMichael Pratt
vgetrandomGetState can call malloc, so this is not a leaf lock. Our staticlockrank builder doesn't support vgetrandom, so it didn't catch this. Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-staticlockranking Change-Id: I6a6a636c36c9172e4ebf9493c10cb23cac29a13f Reviewed-on: https://go-review.googlesource.com/c/go/+/677255 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-05-19runtime: rename ncpu to numCPUStartupMichael Pratt
ncpu is the total logical CPU count at startup. It is never updated. For #73193, we will start using updated CPU counts for updated GOMAXPROCS, making the ncpu name a bit ambiguous. Change to a less ambiguous name. While we're at it, give the OS specific lookup functions a common name, so it can be used outside of osinit later. For #73193. Change-Id: I6a6a636cf21cc60de36b211f3c374080849fc667 Reviewed-on: https://go-review.googlesource.com/c/go/+/672277 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Pratt <mpratt@google.com>
2025-04-03runtime: cleanup M vgetrandom state before dropping PMichael Pratt
When an M is destroyed, we put its vgetrandom state back on the shared list for another M to reuse. This list is simply a slice, so appending to the slice may allocate. Currently this operation is performed in mdestroy, after the P is released, meaning allocation is not allowed. More the cleanup earlier in mdestroy when allocation is still OK. Also add //go:nowritebarrierrec to mdestroy since it runs without a P, which would have caught this bug. Fixes #73141. Change-Id: I6a6a636c3fbf5c6eec09d07a260e39dbb4d2db12 Reviewed-on: https://go-review.googlesource.com/c/go/+/662455 Reviewed-by: Jason Donenfeld <Jason@zx2c4.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com>
2025-03-04runtime: decorate anonymous memory mappingsLénaïc Huard
Leverage the prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ...) API to name the anonymous memory areas. This API has been introduced in Linux 5.17 to decorate the anonymous memory areas shown in /proc/<pid>/maps. This is already used by glibc. See: * https://sourceware.org/git/?p=glibc.git;a=blob;f=malloc/malloc.c;h=27dfd1eb907f4615b70c70237c42c552bb4f26a8;hb=HEAD#l2434 * https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/setvmaname.c;h=ea93a5ffbebc9e5a7e32a297138f465724b4725f;hb=HEAD#l63 This can be useful when investigating the memory consumption of a multi-language program. On a 100% Go program, pprof profiler can be used to profile the memory consumption of the program. But pprof is only aware of what happens within the Go world. On a multi-language program, there could be a doubt about whether the suspicious extra-memory consumption comes from the Go part or the native part. With this change, the following Go program: package main import ( "fmt" "log" "os" ) /* #include <stdlib.h> void f(void) { (void)malloc(1024*1024*1024); } */ import "C" func main() { C.f() data, err := os.ReadFile("/proc/self/maps") if err != nil { log.Fatal(err) } fmt.Println(string(data)) } produces this output: $ GLIBC_TUNABLES=glibc.mem.decorate_maps=1 ~/doc/devel/open-source/go/bin/go run . 00400000-00402000 r--p 00000000 00:21 28451768 /home/lenaic/.cache/go-build/9f/9f25a17baed5a80d03eb080a2ce2a5ff49c17f9a56e28330f0474a2bb74a30a0-d/test_vma_name 00402000-004a4000 r-xp 00002000 00:21 28451768 /home/lenaic/.cache/go-build/9f/9f25a17baed5a80d03eb080a2ce2a5ff49c17f9a56e28330f0474a2bb74a30a0-d/test_vma_name 004a4000-00574000 r--p 000a4000 00:21 28451768 /home/lenaic/.cache/go-build/9f/9f25a17baed5a80d03eb080a2ce2a5ff49c17f9a56e28330f0474a2bb74a30a0-d/test_vma_name 00574000-00575000 r--p 00173000 00:21 28451768 /home/lenaic/.cache/go-build/9f/9f25a17baed5a80d03eb080a2ce2a5ff49c17f9a56e28330f0474a2bb74a30a0-d/test_vma_name 00575000-00580000 rw-p 00174000 00:21 28451768 /home/lenaic/.cache/go-build/9f/9f25a17baed5a80d03eb080a2ce2a5ff49c17f9a56e28330f0474a2bb74a30a0-d/test_vma_name 00580000-005a4000 rw-p 00000000 00:00 0 2e075000-2e096000 rw-p 00000000 00:00 0 [heap] c000000000-c000400000 rw-p 00000000 00:00 0 [anon: Go: heap] c000400000-c004000000 ---p 00000000 00:00 0 [anon: Go: heap reservation] 777f40000000-777f40021000 rw-p 00000000 00:00 0 [anon: glibc: malloc arena] 777f40021000-777f44000000 ---p 00000000 00:00 0 777f44000000-777f44021000 rw-p 00000000 00:00 0 [anon: glibc: malloc arena] 777f44021000-777f48000000 ---p 00000000 00:00 0 777f48000000-777f48021000 rw-p 00000000 00:00 0 [anon: glibc: malloc arena] 777f48021000-777f4c000000 ---p 00000000 00:00 0 777f4c000000-777f4c021000 rw-p 00000000 00:00 0 [anon: glibc: malloc arena] 777f4c021000-777f50000000 ---p 00000000 00:00 0 777f50000000-777f50021000 rw-p 00000000 00:00 0 [anon: glibc: malloc arena] 777f50021000-777f54000000 ---p 00000000 00:00 0 777f55afb000-777f55afc000 ---p 00000000 00:00 0 777f55afc000-777f562fc000 rw-p 00000000 00:00 0 [anon: glibc: pthread stack: 216378] 777f562fc000-777f562fd000 ---p 00000000 00:00 0 777f562fd000-777f56afd000 rw-p 00000000 00:00 0 [anon: glibc: pthread stack: 216377] 777f56afd000-777f56afe000 ---p 00000000 00:00 0 777f56afe000-777f572fe000 rw-p 00000000 00:00 0 [anon: glibc: pthread stack: 216376] 777f572fe000-777f572ff000 ---p 00000000 00:00 0 777f572ff000-777f57aff000 rw-p 00000000 00:00 0 [anon: glibc: pthread stack: 216375] 777f57aff000-777f57b00000 ---p 00000000 00:00 0 777f57b00000-777f58300000 rw-p 00000000 00:00 0 [anon: glibc: pthread stack: 216374] 777f58300000-777f58400000 rw-p 00000000 00:00 0 [anon: Go: page alloc index] 777f58400000-777f5a400000 rw-p 00000000 00:00 0 [anon: Go: heap index] 777f5a400000-777f6a580000 ---p 00000000 00:00 0 [anon: Go: scavenge index] 777f6a580000-777f6a581000 rw-p 00000000 00:00 0 [anon: Go: scavenge index] 777f6a581000-777f7a400000 ---p 00000000 00:00 0 [anon: Go: scavenge index] 777f7a400000-777f8a580000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f8a580000-777f8a581000 rw-p 00000000 00:00 0 [anon: Go: page alloc] 777f8a581000-777f9c430000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f9c430000-777f9c431000 rw-p 00000000 00:00 0 [anon: Go: page alloc] 777f9c431000-777f9e806000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f9e806000-777f9e807000 rw-p 00000000 00:00 0 [anon: Go: page alloc] 777f9e807000-777f9ec00000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f9ec36000-777f9ecb6000 rw-p 00000000 00:00 0 [anon: Go: immortal metadata] 777f9ecb6000-777f9ecc6000 rw-p 00000000 00:00 0 [anon: Go: gc bits] 777f9ecc6000-777f9ecd6000 rw-p 00000000 00:00 0 [anon: Go: allspans array] 777f9ecd6000-777f9ece7000 rw-p 00000000 00:00 0 [anon: Go: immortal metadata] 777f9ece7000-777f9ed67000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f9ed67000-777f9ed68000 rw-p 00000000 00:00 0 [anon: Go: page alloc] 777f9ed68000-777f9ede7000 ---p 00000000 00:00 0 [anon: Go: page summary] 777f9ede7000-777f9ee07000 rw-p 00000000 00:00 0 [anon: Go: page alloc] 777f9ee07000-777f9ee0a000 rw-p 00000000 00:00 0 [anon: glibc: loader malloc] 777f9ee0a000-777f9ee2e000 r--p 00000000 00:21 48158213 /usr/lib/libc.so.6 777f9ee2e000-777f9ef9f000 r-xp 00024000 00:21 48158213 /usr/lib/libc.so.6 777f9ef9f000-777f9efee000 r--p 00195000 00:21 48158213 /usr/lib/libc.so.6 777f9efee000-777f9eff2000 r--p 001e3000 00:21 48158213 /usr/lib/libc.so.6 777f9eff2000-777f9eff4000 rw-p 001e7000 00:21 48158213 /usr/lib/libc.so.6 777f9eff4000-777f9effc000 rw-p 00000000 00:00 0 777f9effc000-777f9effe000 rw-p 00000000 00:00 0 [anon: glibc: loader malloc] 777f9f00a000-777f9f04a000 rw-p 00000000 00:00 0 [anon: Go: immortal metadata] 777f9f04a000-777f9f04c000 r--p 00000000 00:00 0 [vvar] 777f9f04c000-777f9f04e000 r--p 00000000 00:00 0 [vvar_vclock] 777f9f04e000-777f9f050000 r-xp 00000000 00:00 0 [vdso] 777f9f050000-777f9f051000 r--p 00000000 00:21 48158204 /usr/lib/ld-linux-x86-64.so.2 777f9f051000-777f9f07a000 r-xp 00001000 00:21 48158204 /usr/lib/ld-linux-x86-64.so.2 777f9f07a000-777f9f085000 r--p 0002a000 00:21 48158204 /usr/lib/ld-linux-x86-64.so.2 777f9f085000-777f9f087000 r--p 00034000 00:21 48158204 /usr/lib/ld-linux-x86-64.so.2 777f9f087000-777f9f088000 rw-p 00036000 00:21 48158204 /usr/lib/ld-linux-x86-64.so.2 777f9f088000-777f9f089000 rw-p 00000000 00:00 0 7ffc7bfa7000-7ffc7bfc8000 rw-p 00000000 00:00 0 [stack] ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall] The anonymous memory areas are now labelled so that we can see which ones have been allocated by the Go runtime versus which ones have been allocated by the glibc. Fixes #71546 Change-Id: I304e8b4dd7f2477a6da794fd44e9a7a5354e4bf4 Reviewed-on: https://go-review.googlesource.com/c/go/+/646095 Auto-Submit: Alan Donovan <adonovan@google.com> Commit-Queue: Alan Donovan <adonovan@google.com> Reviewed-by: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
2024-10-02runtime: don't acquirem() in vgetrandom unless necessaryJason A. Donenfeld
I noticed in pprof that acquirem() was a bit of a hotspot. It turns out that we can use the same trick that runtime.rand() does, and only acquirem if we're doing something non-nosplit -- in this case, getting a new state -- but otherwise just do getg().m, which is safe because we're inside runtime and don't call split functions. cpu: 11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz │ sec/op │ sec/op vs base │ ParallelGetRandom-16 2.651n ± 4% 2.416n ± 7% -8.87% (p=0.001 n=10) │ B/s │ B/s vs base │ ParallelGetRandom-16 1.406Gi ± 4% 1.542Gi ± 6% +9.72% (p=0.001 n=10) Change-Id: Iae075f4e298b923e499cd01adfabacab725a8684 Reviewed-on: https://go-review.googlesource.com/c/go/+/616738 Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-09-30runtime, internal/syscall/unix: mark getrandom vDSO as non-escapingMateusz Poliwczak
Updates #66779 Updates #69577 Change-Id: I0dea5a30aab87aaa443e7e6646c1d07aa865ac1c GitHub-Last-Rev: 1cea46deb345369346efb2cb320fae1644466322 GitHub-Pull-Request: golang/go#69719 Reviewed-on: https://go-review.googlesource.com/c/go/+/616696 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Commit-Queue: Ian Lance Taylor <iant@google.com> Reviewed-by: Filippo Valsorda <filippo@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com>
2024-09-30runtime: align vgetrandom states to cache lineJason A. Donenfeld
This prevents false sharing, which makes a large difference on machines with several NUMA nodes, such as this dual socket server: cpu: Intel(R) Xeon(R) Gold 6338 CPU @ 2.00GHz │ sec/op │ sec/op vs base │ ParallelGetRandom-128 0.7944n ± 5% 0.4503n ± 0% -43.31% (p=0.000 n=10) │ B/s │ B/s vs base │ ParallelGetRandom-128 4.690Gi ± 5% 8.272Gi ± 0% +76.38% (p=0.000 n=10) Change-Id: Id4421e9a4c190b38aff0be4c59e9067b0a38ccd7 Reviewed-on: https://go-review.googlesource.com/c/go/+/616535 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Jason Donenfeld <Jason@zx2c4.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2024-09-28runtime: use vDSO for getrandom() on linuxJason A. Donenfeld
Linux 6.11 supports calling getrandom() from the vDSO. It operates on a thread-local opaque state allocated with mmap using flags specified by the vDSO. Opaque states are allocated in chunks, ideally ncpu at a time as a hint, rounding up to as many fit in a complete page. On first use, a state is assigned to an m, which owns that state, until the m exits, at which point it is given back to the pool. Performance appears to be quite good: │ sec/op │ sec/op vs base │ Read/4-16 222.45n ± 3% 27.13n ± 6% -87.80% (p=0.000 n=10) │ B/s │ B/s vs base │ Read/4-16 17.15Mi ± 3% 140.61Mi ± 6% +719.82% (p=0.000 n=10) Fixes #69577. Change-Id: Ib6f44e8f2f3940c94d970eaada0eb566ec297dc7 Reviewed-on: https://go-review.googlesource.com/c/go/+/614835 Reviewed-by: Filippo Valsorda <filippo@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com> Auto-Submit: Jason Donenfeld <Jason@zx2c4.com> Reviewed-by: Paul Murphy <murp@ibm.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>