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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-07-06 16:43:19 +0000 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-07-06 16:43:19 +0000 |
| commit | 238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd (patch) | |
| tree | cd8a1b75ba7b3543eb7fe6857f408e7be4d9fd0b /results/classifier/gemma3:27b/syscall/1728116 | |
| parent | 96049c939b1916d80532630d63c14e04d5244f1d (diff) | |
| download | emulator-bug-study-238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd.tar.gz emulator-bug-study-238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd.zip | |
add results
Diffstat (limited to 'results/classifier/gemma3:27b/syscall/1728116')
| -rw-r--r-- | results/classifier/gemma3:27b/syscall/1728116 | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/results/classifier/gemma3:27b/syscall/1728116 b/results/classifier/gemma3:27b/syscall/1728116 new file mode 100644 index 00000000..b161a72f --- /dev/null +++ b/results/classifier/gemma3:27b/syscall/1728116 @@ -0,0 +1,50 @@ + + + +Empty /proc/self/auxv (linux-user) + +The userspace Linux API virtualization used to fake access to /proc/self/auxv, to provide meaningful data for the guest process. + +For newer qemu versions, this fails: The openat() is intercepted, but there's no content: /proc/self/auxv has length zero (i.e. reading from it returns 0 bytes). + +Good: + +$ x86_64-linux-user/qemu-x86_64 /usr/bin/cat /proc/self/auxv | wc -c +256 /proc/self/auxv + +Bad: + +$ x86_64-linux-user/qemu-x86_64 /usr/bin/cat /proc/self/auxv | wc -c +0 /proc/self/auxv + +This worked in 2.7.1, and fails in 2.10.1. + +This causes e.g. any procps-ng-based tool to segfault while reading from /proc/self/auxv in an endless loop (probably worth another bug report...) + +Doing a "git bisect" shows that this commit: https://github.com/qemu/qemu/commit/7c4ee5bcc introduced the problem. + +It might be a simple logic (subtraction in the wrong direction?) or sign-ness error: Adding some logging (to v2.10.1) + +diff --git a/linux-user/syscall.c b/linux-user/syscall.c +index 9b6364a..49285f9 100644 +--- a/linux-user/syscall.c ++++ b/linux-user/syscall.c +@@ -7469,6 +7469,9 @@ static int open_self_auxv(void *cpu_env, int fd) + abi_ulong len = ts->info->auxv_len; + char *ptr; + ++ gemu_log(TARGET_ABI_FMT_lu"\n", len); ++ gemu_log(TARGET_ABI_FMT_ld"\n", len); ++ + /* + * Auxiliary vector is stored in target process stack. + * read in whole auxv vector and copy it to file + +shows this output: + +$ x86_64-linux-user/qemu-x86_64 /usr/bin/cat /proc/self/auxv | wc -c +18446744073709551264 +-352 +0 + +And 352 could be the expected length. \ No newline at end of file |