cmd/cgo: (on riscv64 with gcc-15) FATAL: ThreadSanitizer: memory layout is incompatible, even though ASLR is disabled.

[tianon]

fyi, golang-1.24 reproduced the issue with gcc-15, but before reporting this to gcc, I want to confirm whether this is expected from the golang side or not.

Originally posted by @yuzibo in #64345

This is probably a gcc bug (from the messaging libtsan is spitting out), but just in case it's actually a Go bug, we wanted to start by reporting it to Go first. 🙇

On riscv64 with gcc-15, we're seeing test failures in the testsanitizers tests TestTSAN and TestShared that look like this:

--- FAIL: TestShared (0.00s)
    cshared_test.go:61: skipping msan_shared test on linux/riscv64; -msan option is not supported.
    --- FAIL: TestShared/tsan_shared (121.78s)
        cshared_test.go:112: /usr/bin/setarch riscv64 -R /tmp/TestSharedtsan_shared3507443847/001/tsan_shared exited with exit status 66
            FATAL: ThreadSanitizer: memory layout is incompatible, even though ASLR is disabled.
            Please file a bug.
            ==63940==Process memory map follows:
            	0x002aaaaaa000-0x002aaaaab000	/tmp/TestSharedtsan_shared3507443847/001/tsan_shared
            	0x002aaaaab000-0x002aaaaac000	/tmp/TestSharedtsan_shared3507443847/001/tsan_shared
            	0x002aaaaac000-0x002aaaaad000	/tmp/TestSharedtsan_shared3507443847/001/tsan_shared
            	0x003fe6c51000-0x003fe6c66000	
            	0x003fe6c66000-0x003fe6c82000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
            	0x003fe6c82000-0x003fe6c83000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
            	0x003fe6c83000-0x003fe6c84000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
            	0x003fe6c84000-0x003fe6d07000	/usr/lib/riscv64-linux-gnu/libm.so.6
            	0x003fe6d07000-0x003fe6d08000	/usr/lib/riscv64-linux-gnu/libm.so.6
            	0x003fe6d08000-0x003fe6d09000	/usr/lib/riscv64-linux-gnu/libm.so.6
            	0x003fe6d09000-0x003fe6e5e000	/usr/lib/riscv64-linux-gnu/libc.so.6
            	0x003fe6e5e000-0x003fe6e61000	/usr/lib/riscv64-linux-gnu/libc.so.6
            	0x003fe6e61000-0x003fe6e63000	/usr/lib/riscv64-linux-gnu/libc.so.6
            	0x003fe6e63000-0x003fe6e6f000	
            	0x003fe6e6f000-0x003fe6f09000	/tmp/TestSharedtsan_shared3507443847/001/libtsan_shared.so
            	0x003fe6f09000-0x003fe6f6f000	/tmp/TestSharedtsan_shared3507443847/001/libtsan_shared.so
            	0x003fe6f6f000-0x003fe6f74000	/tmp/TestSharedtsan_shared3507443847/001/libtsan_shared.so
            	0x003fe6f74000-0x003fe6f97000	
            	0x003fe6f97000-0x003fe70b9000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
            	0x003fe70b9000-0x003fe70be000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
            	0x003fe70be000-0x003fe70c6000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
            	0x003fe70c6000-0x003ff7fd6000	
            	0x003ff7fd6000-0x003ff7fd9000	
            	0x003ff7fd9000-0x003ff7fdb000	[vvar]
            	0x003ff7fdb000-0x003ff7fdc000	[vdso]
            	0x003ff7fdc000-0x003ff7ffc000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
            	0x003ff7ffc000-0x003ff7ffe000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
            	0x003ff7ffe000-0x003ff7fff000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
            	0x003ff7fff000-0x003ff8000000	
            	0x003ffffde000-0x004000000000	[stack]
            ==63940==End of process memory map.
--- FAIL: TestTSAN (173.01s)
    --- FAIL: TestTSAN/tsan (35.03s)
        tsan_test.go:95: /usr/bin/setarch riscv64 -R /tmp/TestTSANtsan1239464039/001/tsan exited with exit status 66

[randall77]

@golang/riscv64

[gabyhelp]

Related Issues

• runtime: "ThreadSanitizer: unexpected memory mapping" on ppc64le #54757 (closed)
• misc/cgo/testsanitizers: ThreadSantitizer test fails #14902 (closed)
• misc/cgo/testsanitizers: fails on ubuntu 16.04 pre-release #15185 (closed)
• runtime: MSAN failed to run on arm64 with non-PIE builds #33712 (closed)
• build: testsanitizers fails on linux-amd64-clang builder #12818 (closed)
• x/build: new linux-arm64-msan-clang15 builder isn't passing at tip yet #71614
• runtime: TestASAN fails with SEGV on unknown address on linux/riscv64 #57691
• cmd/cgo: ThreadSanitizer barks about data races in all.bash #14602 (closed)
• msan/tsan tests run (and FAIL) for clang version < 3.6 #14570 (closed)
• runtime: clang builder broken #12814 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[prattmic]

FWIW, TSAN's expected memory layout is visible at https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/tsan/rtl/tsan_platform.h#L684-L735.

Is this a 39-bit address space system, or 48-bit?

The printed mappings appear to be completely within the 48-bit address space layout (application mappings ending at 0xe000000000), but completely above the 39-bit layout (application mappings ending at 0xf00000000).

[prattmic]

Also note that there are very recent changes to TSAN for riscv, which perhaps aren't in GCC 15?

llvm/llvm-project@9958b1c
llvm/llvm-project@5886a27

cc @4a6f656c

[tianon]

These results are from a SiFive Unmatched running Debian Unstable (hopefully that implies the answer you need; if not, I'll try to get someone from the Debian riscv porters group to contribute to this thread better than I can 😅)

[prattmic]

Thanks, https://www.sifive.com/document-file/hifive-unmatched-datasheet says it has a SiFive FU740-C000 CPU, and https://www.sifive.com/document-file/freedom-u740-c000-manual says "Sv39 virtual memory support", so sounds like 39-bit.

[prattmic]

Actually, regarding the TSAN changes (#75553 (comment)), I think Go's prebuilt TSAN syso would need to include the change, not GCC.

Per https://go.dev/cl/690497 src/runtime/race/README, the riscv syso is built at LLVM c3c24be13f7928460ca1e2fe613a1146c868854e, which I believe includes the changes I linked to.

[markdryan]

The original report mentions Go 1.24 and gcc-15. Do we know whether the bug reproduces on master with gcc-15?

[yuzibo]

The original report mentions Go 1.24 and gcc-15. Do we know whether the bug reproduces on master with gcc-15?

At least golang-1.25 can reproduce the issue with gcc-15 also.

With the help of @mengzhuo, we can reproduce the issue with a minimal test case:

rv@deb01:~$ cat simple_tsan_test.c 
// simple_tsan_test.c
#include <pthread.h>
#include <stdio.h>

int data = 0;

void* thread_func(void* arg) {
    data = 42;
    return NULL;
}

int main() {
    pthread_t thread;
    pthread_create(&thread, NULL, thread_func, NULL);
    data = 43; 
    pthread_join(thread, NULL);
    printf("data = %d\n", data);
    return 0;
}

gcc-15 -fsanitize=thread -g -o simple_tsan_test simple_tsan_test.c -lpthread

rv@deb01:~$ setarch riscv64 -R ./simple_tsan_test 
FATAL: ThreadSanitizer: memory layout is incompatible, even though ASLR is disabled.
Please file a bug.
==338692==Process memory map follows:
	0x002aaaaaa000-0x002aaaaab000	/home/rv/simple_tsan_test
	0x002aaaaab000-0x002aaaaac000	/home/rv/simple_tsan_test
	0x002aaaaac000-0x002aaaaad000	/home/rv/simple_tsan_test
	0x003fe6d7b000-0x003fe6dfe000	/usr/lib/riscv64-linux-gnu/libm.so.6
	0x003fe6dfe000-0x003fe6dff000	/usr/lib/riscv64-linux-gnu/libm.so.6
	0x003fe6dff000-0x003fe6e00000	/usr/lib/riscv64-linux-gnu/libm.so.6
	0x003fe6e00000-0x003fe6f22000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
	0x003fe6f22000-0x003fe6f27000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
	0x003fe6f27000-0x003fe6f2f000	/usr/lib/riscv64-linux-gnu/libtsan.so.2.0.0
	0x003fe6f2f000-0x003ff7e3e000	
	0x003ff7e3e000-0x003ff7e5a000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
	0x003ff7e5a000-0x003ff7e5b000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
	0x003ff7e5b000-0x003ff7e5c000	/usr/lib/riscv64-linux-gnu/libgcc_s.so.1
	0x003ff7e5c000-0x003ff7fb1000	/usr/lib/riscv64-linux-gnu/libc.so.6
	0x003ff7fb1000-0x003ff7fb4000	/usr/lib/riscv64-linux-gnu/libc.so.6
	0x003ff7fb4000-0x003ff7fb6000	/usr/lib/riscv64-linux-gnu/libc.so.6
	0x003ff7fb6000-0x003ff7fc4000	
	0x003ff7fc5000-0x003ff7fd9000	
	0x003ff7fd9000-0x003ff7fdb000	[vvar]
	0x003ff7fdb000-0x003ff7fdc000	[vdso]
	0x003ff7fdc000-0x003ff7ffc000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
	0x003ff7ffc000-0x003ff7ffe000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
	0x003ff7ffe000-0x003ff7fff000	/usr/lib/riscv64-linux-gnu/ld-linux-riscv64-lp64d.so.1
	0x003ff7fff000-0x003ff8000000	
	0x003ffffdf000-0x004000000000	[stack]
==338692==End of process memory map.

[JunyangShao]

@golang/compiler