diff options
Diffstat (limited to 'results/classifier/118/all/1906193')
| -rw-r--r-- | results/classifier/118/all/1906193 | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/results/classifier/118/all/1906193 b/results/classifier/118/all/1906193 new file mode 100644 index 00000000..16810e6a --- /dev/null +++ b/results/classifier/118/all/1906193 @@ -0,0 +1,188 @@ +permissions: 0.960 +device: 0.951 +user-level: 0.951 +architecture: 0.951 +register: 0.951 +arm: 0.950 +virtual: 0.939 +semantic: 0.936 +PID: 0.934 +debug: 0.934 +performance: 0.931 +graphic: 0.925 +risc-v: 0.923 +files: 0.916 +kernel: 0.915 +socket: 0.915 +assembly: 0.912 +ppc: 0.912 +peripherals: 0.909 +boot: 0.903 +mistranslation: 0.901 +network: 0.891 +vnc: 0.890 +KVM: 0.890 +hypervisor: 0.889 +VMM: 0.887 +TCG: 0.876 +x86: 0.868 +i386: 0.841 + +riscv32 user mode emulation: fork return values broken + +When running in a chroot with riscv32 (on x86_64; qemu git master as of today): + +The following short program forks; the child immediately returns with exit(42). The parent checks for the return value - and obtains 40! + +gcc-10.2 + +=============================================== +#include <stdlib.h> +#include <unistd.h> +#include <stdio.h> +#include <sys/wait.h> + +main(c, v) + int c; + char **v; +{ + pid_t pid, p; + int s, i, n; + + s = 0; + pid = fork(); + if (pid == 0) + exit(42); + + /* wait for the process */ + p = wait(&s); + if (p != pid) + exit (255); + + if (WIFEXITED(s)) + { + int r=WEXITSTATUS(s); + if (r!=42) { + printf("child wants to return %i (0x%X), parent received %i (0x%X), difference %i\n",42,42,r,r,r-42); + } + } +} +=============================================== + +(riscv-ilp32 chroot) farino /tmp # ./wait-test-short +child wants to return 42 (0x2A), parent received 40 (0x28), difference -2 + +=============================================== +(riscv-ilp32 chroot) farino /tmp # gcc --version +gcc (Gentoo 10.2.0-r1 p2) 10.2.0 +Copyright (C) 2020 Free Software Foundation, Inc. +Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es +gibt KEINE Garantie; auch nicht für MARKTGÄNGIGKEIT oder FÜR SPEZIELLE ZWECKE. + +(riscv-ilp32 chroot) farino /tmp # ld --version +GNU ld (Gentoo 2.34 p6) 2.34.0 +Copyright (C) 2020 Free Software Foundation, Inc. +This program is free software; you may redistribute it under the terms of +the GNU General Public License version 3 or (at your option) a later version. +This program has absolutely no warranty. + +This is the (statically linked) binary resulting from the source; with it the problem can be demonstrated "standalone", without any other rv32 libraries or a complete chroot, just running the binary with qemu-riscv32. + +Generated with + +(riscv-ilp32 chroot) farino /tmp # gcc -static -o wait-test-short -g wait-test-short.c + + +I can confirm that the same binary works fine with qemu system emulation: + +(riscv-ilp32 qemu) (none) /tmp # ./wait-test-short +(riscv-ilp32 qemu) (none) /tmp # + + +Here's the (abbreviated) output of strace'ing qemu: + +farino ~ # strace -f /usr/bin/qemu-riscv32 /chroot/riscv-ilp32/tmp/wait-test-short +execve("/usr/bin/qemu-riscv32", ["/usr/bin/qemu-riscv32", "/chroot/riscv-ilp32/tmp/wait-tes"...], 0x7ffd95fb1330 /* 40 vars */) = 0 + +[...] + +[pid 16569] uname({sysname="Linux", nodename="farino", ...}) = 0 +[pid 16569] lstat("/chroot", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 +[pid 16569] lstat("/chroot/riscv-ilp32", {st_mode=S_IFDIR|S_ISGID|0755, st_size=4096, ...}) = 0 +[pid 16569] lstat("/chroot/riscv-ilp32/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=4096, ...}) = 0 +[pid 16569] lstat("/chroot/riscv-ilp32/tmp/wait-test-short", {st_mode=S_IFREG|0755, st_size=445632, ...}) = 0 +[pid 16569] mmap(0x413f1000, 135168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x413f1000 +[pid 16569] mprotect(0x413eb000, 8192, PROT_READ) = 0 +[pid 16569] rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], NULL, 8) = 0 +[pid 16569] clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x1339710) = 16571 +strace: Process 16571 attached +[pid 16571] set_robust_list(0x1339720, 24 <unfinished ...> +[pid 16569] rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], NULL, 8) = 0 +[pid 16571] <... set_robust_list resumed>) = 0 +[pid 16569] rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 +[pid 16571] rt_sigprocmask(SIG_SETMASK, ~[ILL FPE SEGV RTMIN RT_1], ~[KILL STOP RTMIN RT_1], 8) = 0 +[pid 16571] rt_sigprocmask(SIG_BLOCK, ~[], ~[ILL FPE KILL SEGV STOP RTMIN RT_1], 8) = 0 +[pid 16571] clone(child_stack=0x7fe5b73871f0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tid=[16572], tls=0x7fe5b7387640, child_tidptr=0x7fe5b7387910) = 16572 +[pid 16571] rt_sigprocmask(SIG_SETMASK, ~[ILL FPE KILL SEGV STOP RTMIN RT_1], NULL, 8) = 0 +[pid 16571] rt_sigprocmask(SIG_SETMASK, ~[KILL STOP RTMIN RT_1], NULL, 8) = 0 +[pid 16571] gettid() = 16571 +[pid 16571] rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], NULL, 8) = 0 +[pid 16571] rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 +[pid 16569] waitid(P_ALL, -1, <unfinished ...> +[pid 16571] exit_group(42) = ? +strace: Process 16572 attached +[pid 16572] +++ exited with 42 +++ +[pid 16571] +++ exited with 42 +++ +[pid 16569] <... waitid resumed>{si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=16571, si_uid=0, si_status=42, si_utime=3472328296226648184, si_stime=3475143045726351408}, WEXITED, NULL) = 0 +[pid 16569] --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=16571, si_uid=0, si_status=42, si_utime=0, si_stime=0} --- +[pid 16569] statx(1, "", AT_STATX_SYNC_AS_STAT|AT_EMPTY_PATH, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFCHR|0600, stx_size=0, ...}) = 0 +[pid 16569] write(1, "child wants to return 42 (0x2A),"..., 74child wants to return 42 (0x2A), parent received 40 (0x28), difference -2 +) = 74 +[pid 16569] brk(0x13c1000) = 0x13c1000 +[pid 16569] brk(0x13c0000) = 0x13c0000 +[pid 16569] exit_group(0) = ? +[pid 16570] <... futex resumed>) = ? +[pid 16570] +++ exited with 0 +++ ++++ exited with 0 +++ + + +Here's qemu's own strace log: + +farino ~ # /usr/bin/qemu-riscv32 -strace /chroot/riscv-ilp32/tmp/wait-test-short +10123 brk(NULL) = 0x00073000 +10123 brk(0x00073880) = 0x00073880 +10123 uname(0x407ffed8) = 0 +10123 readlinkat(AT_FDCWD,"/proc/self/exe",0x407feff0,4096) = 39 +10123 brk(0x00094880) = 0x00094880 +10123 brk(0x00095000) = 0x00095000 +10123 mprotect(0x0006e000,8192,PROT_READ) = 0 +10123 clone(CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|0x11,child_stack=0x00000000,parent_tidptr=0x00000000,tls=0x00000000,child_tidptr=0x00073068) = 10125 +10123 clone(CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|0x11,child_stack=0x00000000,parent_tidptr=0x00000000,tls=0x00000000,child_tidptr=0x00073068) = 0 +10125 exit_group(42) +10123 waitid(0,-1,0x407fff8c,0x4) = 0 +10123 statx(1,"",AT_EMPTY_PATH,STATX_BASIC_STATS,0x407ff8e8) = 0 +child wants to return 42 (0x2A), parent received 40 (0x28), difference -2 +10123 write(1,0x73ad0,74) = 74 +10123 exit_group(0) + + +I have sent a patch, you can see it here: https://patchwork.ozlabs.org/project/qemu-devel/list/?series=221381 + +It seems like QEMU's waitid implementation has a bug with handling the status. + +Thanks a lot! Will test and post the result on monday when I'm back home. + +After applying this patch on top of qemu-5.2.0, I can confirm that it fixes the problem. + +Thank you!! + +Just as a general remark, while this specific problem seems to be solved, there may still be issues surrounding waitid(). + +(With this patch applied, in a rather complex environment I see bash processes hanging in an infinite loop, with waitid involved. I am working on isolating the problem and providing a simple test case, but so far I have not even found the code triggering it.) + +Can you add a Tested-by: tag to the patch? + +Done (took a while to figure out how...) + +A fix has been merged into master. + |