| Message ID | 20210824024358.4183342-1-jun.miao@windriver.com |
|---|---|
| State | New |
| Headers | show |
| Series | [V3] selftests/x86: Fix error: variably modified 'altstack_data' at file scope | expand |
Hi all, What about this patch? Thanks Jun On 8/24/21 10:43 AM, Jun Miao wrote: > Based on glibc 2.33 -> 2.34, there is one new feature: > > NEWS for version 2.34 > ===================== > Major new features: > * Add _SC_MINSIGSTKSZ and _SC_SIGSTKSZ. When _DYNAMIC_STACK_SIZE_SOURCE > or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are no longer > constant on Linux. MINSIGSTKSZ is redefined to sysconf(_SC_MINSIGSTKSZ) > and SIGSTKSZ is redefined to sysconf (_SC_SIGSTKSZ). This supports > dynamic sized register sets for modern architectural features like > Arm SVE. > ===================== > > If _SC_SIGSTKSZ_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ > are redefined as: > > /* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ). */ > # undef SIGSTKSZ > # define SIGSTKSZ sysconf (_SC_SIGSTKSZ) > > /* Minimum stack size for a signal handler: SIGSTKSZ. */ > # undef MINSIGSTKSZ > # define MINSIGSTKSZ SIGSTKSZ > > Compilation will fail if the source assumes constant MINSIGSTKSZ or > SIGSTKSZ. > > Build error with the GNU C Library 2.34: > DEBUG: | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope > | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope > DEBUG: | 150 | static char altstack_data[SIGSTKSZ]; > | 150 | static char altstack_data[SIGSTKSZ]; > DEBUG: | | ^~~~~~~~~~~~~ > > DEBUG: | single_step_syscall.c:60:22: error: variably modified 'altstack_data' at file scope > DEBUG: | 60 | static unsigned char altstack_data[SIGSTKSZ]; > DEBUG: | | ^~~~~~~~~~~~~ > > Link: https://sourceware.org/pipermail/libc-alpha/2021-January/121996.html > Link: https://sourceware.org/pipermail/libc-alpha/2021-August/129718.html > Suggested-by: Jianwei Hu <jianwei.hu@windriver.com> > Signed-off-by: Jun Miao <jun.miao@windriver.com> > --- > tools/testing/selftests/x86/mov_ss_trap.c | 4 ++-- > tools/testing/selftests/x86/sigreturn.c | 7 +++---- > tools/testing/selftests/x86/single_step_syscall.c | 4 ++-- > tools/testing/selftests/x86/syscall_arg_fault.c | 7 +++---- > 4 files changed, 10 insertions(+), 12 deletions(-) > > diff --git a/tools/testing/selftests/x86/mov_ss_trap.c b/tools/testing/selftests/x86/mov_ss_trap.c > index 6da0ac3f0135..cc3de6ff9fba 100644 > --- a/tools/testing/selftests/x86/mov_ss_trap.c > +++ b/tools/testing/selftests/x86/mov_ss_trap.c > @@ -47,7 +47,6 @@ > unsigned short ss; > extern unsigned char breakpoint_insn[]; > sigjmp_buf jmpbuf; > -static unsigned char altstack_data[SIGSTKSZ]; > > static void enable_watchpoint(void) > { > @@ -250,13 +249,14 @@ int main() > if (sigsetjmp(jmpbuf, 1) == 0) { > printf("[RUN]\tMOV SS; SYSENTER\n"); > stack_t stack = { > - .ss_sp = altstack_data, > + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), > .ss_size = SIGSTKSZ, > }; > if (sigaltstack(&stack, NULL) != 0) > err(1, "sigaltstack"); > sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND | SA_ONSTACK); > nr = SYS_getpid; > + free(stack.ss_sp); > /* Clear EBP first to make sure we segfault cleanly. */ > asm volatile ("xorl %%ebp, %%ebp; mov %[ss], %%ss; SYSENTER" : "+a" (nr) > : [ss] "m" (ss) : "flags", "rcx" > diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c > index 57c4f67f16ef..5d7961a5f7f6 100644 > --- a/tools/testing/selftests/x86/sigreturn.c > +++ b/tools/testing/selftests/x86/sigreturn.c > @@ -138,9 +138,6 @@ static unsigned short LDT3(int idx) > return (idx << 3) | 7; > } > > -/* Our sigaltstack scratch space. */ > -static char altstack_data[SIGSTKSZ]; > - > static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), > int flags) > { > @@ -771,7 +768,8 @@ int main() > setup_ldt(); > > stack_t stack = { > - .ss_sp = altstack_data, > + /* Our sigaltstack scratch space. */ > + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), > .ss_size = SIGSTKSZ, > }; > if (sigaltstack(&stack, NULL) != 0) > @@ -872,5 +870,6 @@ int main() > total_nerrs += test_nonstrict_ss(); > #endif > > + free(stack.ss_sp); > return total_nerrs ? 1 : 0; > } > diff --git a/tools/testing/selftests/x86/single_step_syscall.c b/tools/testing/selftests/x86/single_step_syscall.c > index 120ac741fe44..9a30f443e928 100644 > --- a/tools/testing/selftests/x86/single_step_syscall.c > +++ b/tools/testing/selftests/x86/single_step_syscall.c > @@ -57,7 +57,6 @@ static void clearhandler(int sig) > > static volatile sig_atomic_t sig_traps, sig_eflags; > sigjmp_buf jmpbuf; > -static unsigned char altstack_data[SIGSTKSZ]; > > #ifdef __x86_64__ > # define REG_IP REG_RIP > @@ -210,7 +209,7 @@ int main() > unsigned long nr = SYS_getpid; > printf("[RUN]\tSet TF and check SYSENTER\n"); > stack_t stack = { > - .ss_sp = altstack_data, > + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), > .ss_size = SIGSTKSZ, > }; > if (sigaltstack(&stack, NULL) != 0) > @@ -219,6 +218,7 @@ int main() > SA_RESETHAND | SA_ONSTACK); > sethandler(SIGILL, print_and_longjmp, SA_RESETHAND); > set_eflags(get_eflags() | X86_EFLAGS_TF); > + free(stack.ss_sp); > /* Clear EBP first to make sure we segfault cleanly. */ > asm volatile ("xorl %%ebp, %%ebp; SYSENTER" : "+a" (nr) :: "flags", "rcx" > #ifdef __x86_64__ > diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c > index bff474b5efc6..461fa41a4d02 100644 > --- a/tools/testing/selftests/x86/syscall_arg_fault.c > +++ b/tools/testing/selftests/x86/syscall_arg_fault.c > @@ -17,9 +17,6 @@ > > #include "helpers.h" > > -/* Our sigaltstack scratch space. */ > -static unsigned char altstack_data[SIGSTKSZ]; > - > static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), > int flags) > { > @@ -104,7 +101,8 @@ static void sigill(int sig, siginfo_t *info, void *ctx_void) > int main() > { > stack_t stack = { > - .ss_sp = altstack_data, > + /* Our sigaltstack scratch space. */ > + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), > .ss_size = SIGSTKSZ, > }; > if (sigaltstack(&stack, NULL) != 0) > @@ -233,5 +231,6 @@ int main() > set_eflags(get_eflags() & ~X86_EFLAGS_TF); > #endif > > + free(stack.ss_sp); > return 0; > }
On 9/2/21 2:45 AM, Jun Miao wrote: > Hi all, > > What about this patch? > > Thanks > Jun > > > On 8/24/21 10:43 AM, Jun Miao wrote: >> Based on glibc 2.33 -> 2.34, there is one new feature: >> Please don't top post. It is applied to linux-kselftest next for Linux 5.15-rc1 https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=next thanks, -- Shuah
===================== Major new features: * Add _SC_MINSIGSTKSZ and _SC_SIGSTKSZ. When _DYNAMIC_STACK_SIZE_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are no longer constant on Linux. MINSIGSTKSZ is redefined to sysconf(_SC_MINSIGSTKSZ) and SIGSTKSZ is redefined to sysconf (_SC_SIGSTKSZ). This supports dynamic sized register sets for modern architectural features like Arm SVE. ===================== If _SC_SIGSTKSZ_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are redefined as: /* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ). */ # undef SIGSTKSZ # define SIGSTKSZ sysconf (_SC_SIGSTKSZ) /* Minimum stack size for a signal handler: SIGSTKSZ. */ # undef MINSIGSTKSZ # define MINSIGSTKSZ SIGSTKSZ Compilation will fail if the source assumes constant MINSIGSTKSZ or SIGSTKSZ. Build error with the GNU C Library 2.34: DEBUG: | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope DEBUG: | 150 | static char altstack_data[SIGSTKSZ]; | 150 | static char altstack_data[SIGSTKSZ]; DEBUG: | | ^~~~~~~~~~~~~ DEBUG: | single_step_syscall.c:60:22: error: variably modified 'altstack_data' at file scope DEBUG: | 60 | static unsigned char altstack_data[SIGSTKSZ]; DEBUG: | | ^~~~~~~~~~~~~ Link: https://sourceware.org/pipermail/libc-alpha/2021-January/121996.html Link: https://sourceware.org/pipermail/libc-alpha/2021-August/129718.html Suggested-by: Jianwei Hu <jianwei.hu@windriver.com> Signed-off-by: Jun Miao <jun.miao@windriver.com> --- tools/testing/selftests/x86/mov_ss_trap.c | 4 ++-- tools/testing/selftests/x86/sigreturn.c | 7 +++---- tools/testing/selftests/x86/single_step_syscall.c | 4 ++-- tools/testing/selftests/x86/syscall_arg_fault.c | 7 +++---- 4 files changed, 10 insertions(+), 12 deletions(-) diff --git a/tools/testing/selftests/x86/mov_ss_trap.c b/tools/testing/selftests/x86/mov_ss_trap.c index 6da0ac3f0135..cc3de6ff9fba 100644 --- a/tools/testing/selftests/x86/mov_ss_trap.c +++ b/tools/testing/selftests/x86/mov_ss_trap.c @@ -47,7 +47,6 @@ unsigned short ss; extern unsigned char breakpoint_insn[]; sigjmp_buf jmpbuf; -static unsigned char altstack_data[SIGSTKSZ]; static void enable_watchpoint(void) { @@ -250,13 +249,14 @@ int main() if (sigsetjmp(jmpbuf, 1) == 0) { printf("[RUN]\tMOV SS; SYSENTER\n"); stack_t stack = { - .ss_sp = altstack_data, + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), .ss_size = SIGSTKSZ, }; if (sigaltstack(&stack, NULL) != 0) err(1, "sigaltstack"); sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND | SA_ONSTACK); nr = SYS_getpid; + free(stack.ss_sp); /* Clear EBP first to make sure we segfault cleanly. */ asm volatile ("xorl %%ebp, %%ebp; mov %[ss], %%ss; SYSENTER" : "+a" (nr) : [ss] "m" (ss) : "flags", "rcx" diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c index 57c4f67f16ef..5d7961a5f7f6 100644 --- a/tools/testing/selftests/x86/sigreturn.c +++ b/tools/testing/selftests/x86/sigreturn.c @@ -138,9 +138,6 @@ static unsigned short LDT3(int idx) return (idx << 3) | 7; } -/* Our sigaltstack scratch space. */ -static char altstack_data[SIGSTKSZ]; - static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -771,7 +768,8 @@ int main() setup_ldt(); stack_t stack = { - .ss_sp = altstack_data, + /* Our sigaltstack scratch space. */ + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), .ss_size = SIGSTKSZ, }; if (sigaltstack(&stack, NULL) != 0) @@ -872,5 +870,6 @@ int main() total_nerrs += test_nonstrict_ss(); #endif + free(stack.ss_sp); return total_nerrs ? 1 : 0; } diff --git a/tools/testing/selftests/x86/single_step_syscall.c b/tools/testing/selftests/x86/single_step_syscall.c index 120ac741fe44..9a30f443e928 100644 --- a/tools/testing/selftests/x86/single_step_syscall.c +++ b/tools/testing/selftests/x86/single_step_syscall.c @@ -57,7 +57,6 @@ static void clearhandler(int sig) static volatile sig_atomic_t sig_traps, sig_eflags; sigjmp_buf jmpbuf; -static unsigned char altstack_data[SIGSTKSZ]; #ifdef __x86_64__ # define REG_IP REG_RIP @@ -210,7 +209,7 @@ int main() unsigned long nr = SYS_getpid; printf("[RUN]\tSet TF and check SYSENTER\n"); stack_t stack = { - .ss_sp = altstack_data, + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), .ss_size = SIGSTKSZ, }; if (sigaltstack(&stack, NULL) != 0) @@ -219,6 +218,7 @@ int main() SA_RESETHAND | SA_ONSTACK); sethandler(SIGILL, print_and_longjmp, SA_RESETHAND); set_eflags(get_eflags() | X86_EFLAGS_TF); + free(stack.ss_sp); /* Clear EBP first to make sure we segfault cleanly. */ asm volatile ("xorl %%ebp, %%ebp; SYSENTER" : "+a" (nr) :: "flags", "rcx" #ifdef __x86_64__ diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c index bff474b5efc6..461fa41a4d02 100644 --- a/tools/testing/selftests/x86/syscall_arg_fault.c +++ b/tools/testing/selftests/x86/syscall_arg_fault.c @@ -17,9 +17,6 @@ #include "helpers.h" -/* Our sigaltstack scratch space. */ -static unsigned char altstack_data[SIGSTKSZ]; - static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -104,7 +101,8 @@ static void sigill(int sig, siginfo_t *info, void *ctx_void) int main() { stack_t stack = { - .ss_sp = altstack_data, + /* Our sigaltstack scratch space. */ + .ss_sp = malloc(sizeof(char) * SIGSTKSZ), .ss_size = SIGSTKSZ, }; if (sigaltstack(&stack, NULL) != 0) @@ -233,5 +231,6 @@ int main() set_eflags(get_eflags() & ~X86_EFLAGS_TF); #endif + free(stack.ss_sp); return 0; }