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Diffstat (limited to 'results/classifier/user-mode-bugs/1361')
| -rw-r--r-- | results/classifier/user-mode-bugs/1361 | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/results/classifier/user-mode-bugs/1361 b/results/classifier/user-mode-bugs/1361 new file mode 100644 index 000000000..c4da99cfa --- /dev/null +++ b/results/classifier/user-mode-bugs/1361 @@ -0,0 +1,22 @@ + + +ppc64le linux user emulation w/ 64KiB pages seems broken since v5.0.0 +Description of problem: +[Our (snmalloc's)](https://github.com/microsoft/snmalloc) CI includes running a PowerPC64 little-endian Linux build inside qemu, running with 64KiB pages as, at least, Debian runs them by default. As reported [over there](https://github.com/microsoft/snmalloc/issues/576), this broke when GitHub's CI runners moved from Ubuntu Focal (20.04) to Jammy (22.04), bringing qemu from v4.2 to v6.2. + +The failing test case appears to die of an erroneous `SIGSEGV` `SEGV_MAPERR`: +``` +--- SIGSEGV {si_signo=SIGSEGV, si_code=1, si_addr=0x0000004001be5000} --- +``` +despite that address nominally being mapped by the last memory syscall to touch that area +``` +openat(AT_FDCWD,"/usr/powerpc64le-linux-gnu/lib/libstdc++.so.6",O_RDONLY|O_CLOEXEC) = 4 +[...] +mmap(0x0000004001bd0000,131072,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_DENYWRITE|MAP_FIXED,4,0x2f0000) = 0x4001bd0000 +``` + +Bisection reveals that the breakage first occurred with 4dcf078f094d436866ef793aa25c96fba85ac8d0, though I suspect this is merely the commit that exposes some underlying bug rather than being the actual root cause. +Steps to reproduce: +Run a ppc64el Linux executable under `qemu-user` with `-p 65536`. +Additional information: +Please advise what more would be useful. |