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Diffstat (limited to 'results/classifier/118/virtual/1405')
| -rw-r--r-- | results/classifier/118/virtual/1405 | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/results/classifier/118/virtual/1405 b/results/classifier/118/virtual/1405 new file mode 100644 index 00000000..d58227d7 --- /dev/null +++ b/results/classifier/118/virtual/1405 @@ -0,0 +1,151 @@ +register: 0.931 +virtual: 0.929 +semantic: 0.917 +device: 0.914 +arm: 0.914 +PID: 0.910 +assembly: 0.910 +graphic: 0.903 +i386: 0.901 +debug: 0.899 +kernel: 0.893 +permissions: 0.884 +risc-v: 0.878 +socket: 0.878 +architecture: 0.873 +performance: 0.869 +vnc: 0.868 +files: 0.863 +boot: 0.847 +TCG: 0.834 +x86: 0.833 +user-level: 0.832 +network: 0.821 +VMM: 0.816 +ppc: 0.796 +KVM: 0.792 +peripherals: 0.792 +hypervisor: 0.778 +mistranslation: 0.643 + +linux-user: calling SYS_get_thread_area and SYS_get_thread_area has incorrent result on multithread environment +Description of problem: + +Steps to reproduce: +1. Compile test.out by Command and source code: +``` +gcc -m32 -g test.c -lpthread -o test.out +``` +``` +#include <sys/syscall.h> +#include <unistd.h> +#include <stdio.h> +#include <pthread.h> +#include <asm/ldt.h> + +static inline int set_thread_area( struct user_desc *ptr ) +{ + return syscall( SYS_set_thread_area, ptr ); +} + +static inline int get_thread_area( struct user_desc *ptr ) +{ + return syscall( SYS_get_thread_area, ptr ); +} + +static unsigned int entry_number; + +static void* start_routine(void* ptr) +{ + struct user_desc user_desc0 = { entry_number }; + struct user_desc user_desc1 = { entry_number }; + struct user_desc user_desc2 = { entry_number }; + get_thread_area(&user_desc0); + printf("child thread: %u\n", user_desc0.base_addr); + + user_desc1.base_addr = 2; + user_desc1.limit = 0xFFF; + user_desc1.seg_32bit = 1; + set_thread_area( &user_desc1 ); + + get_thread_area(&user_desc2); + printf("child thread: %u\n", user_desc2.base_addr); + return NULL; +} + +int main(void) { + struct user_desc user_desc0 = { -1 }, user_desc1 = { 0 }, user_desc2 = { 0 }; + user_desc0.seg_32bit = 1; + user_desc0.useable = 1; + set_thread_area( &user_desc0 ); + + entry_number = user_desc0.entry_number; + + user_desc1.entry_number = entry_number; + user_desc1.base_addr = 1; + user_desc1.limit = 0xFFF; + user_desc1.seg_32bit = 1; + set_thread_area( &user_desc1 ); + + pthread_t thread_id; + pthread_create(&thread_id, NULL, &start_routine, NULL); + pthread_join(thread_id, NULL); + + user_desc2.entry_number = entry_number; + get_thread_area(&user_desc2); + printf("main thread: %u\n", user_desc2.base_addr); // main thread: 1 + return 0; +} + ``` +2. Correct Result: +``` +child thread: 1 +child thread: 2 +main thread: 1 +``` +qemu-i386 Print Result: +``` +child thread: 1 +child thread: 2 +main thread: 2 +``` +Additional information: +patch for fix the bug: + +https://lists.nongnu.org/archive/html/qemu-devel/2023-02/msg02203.html + +CPUX86State::gdt::base on differect threads must have different vaules, but it points to same memory. +value of CPUX86State::gdt::base must be copied when clone thread. + +https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/kernel/tls.c + +SYS_set_thread_area call do_set_thread_area in kernel, it set user_desc to different memroy area on differernt threads. tls_array is in thread local memory. + +``` +static void set_tls_desc(struct task_struct *p, int idx, + const struct user_desc *info, int n) +{ + struct thread_struct *t = &p->thread; + struct desc_struct *desc = &t->tls_array[idx - GDT_ENTRY_TLS_MIN]; + int cpu; + + /* + * We must not get preempted while modifying the TLS. + */ + cpu = get_cpu(); + + while (n-- > 0) { + if (LDT_empty(info) || LDT_zero(info)) + memset(desc, 0, sizeof(*desc)); + else + fill_ldt(desc, info); + ++info; + ++desc; + } + + if (t == ¤t->thread) + load_TLS(t, cpu); + + put_cpu(); +} +``` |