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      1 /*
      2  * Copyright (c) 2015   Author: Oleg Nesterov <oleg (at) redhat.com>
      3  *                      Modify: Li Wang <liwang (at) redhat.com>
      4  *
      5  * This program is free software; you can redistribute it and/or modify it
      6  * under the terms of version 2 of the GNU General Public License as
      7  * published by the Free Software Foundation.
      8  *
      9  * This program is distributed in the hope that it would be useful, but
     10  * WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     12  *
     13  * you should have received a copy of the GNU General Public License along
     14  * with this program; if not, write the Free Software Foundation, Inc.,
     15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
     16  */
     17 
     18 /*
     19  * Description:
     20  *
     21  *      save_xstate_sig()->drop_init_fpu() doesn't look right. setup_rt_frame()
     22  *      can fail after that, in this case the next setup_rt_frame() triggered
     23  *      by SIGSEGV won't save fpu simply because the old state was lost. This
     24  *      obviously mean that fpu won't be restored after sys_rt_sigreturn() from
     25  *      SIGSEGV handler.
     26  *
     27  *      These commits fix the issue on v3.17-rc3-3 stable kernel:
     28  *
     29  *      commit df24fb859a4e200d9324e2974229fbb7adf00aef
     30  * 		Author: Oleg Nesterov <oleg (at) redhat.com>
     31  * 		Date:   Tue Sep 2 19:57:17 2014 +0200
     32  *
     33  *      commit 66463db4fc5605d51c7bb81d009d5bf30a783a2c
     34  *               Author: Oleg Nesterov <oleg (at) redhat.com>
     35  *               Date:   Tue Sep 2 19:57:13 2014 +0200
     36  *
     37  * Reproduce:
     38  *	Test-case (needs -O2).
     39  */
     40 
     41 #include <stdio.h>
     42 #include <signal.h>
     43 #include <unistd.h>
     44 #include <sys/syscall.h>
     45 #include <sys/mman.h>
     46 #include <pthread.h>
     47 #include <assert.h>
     48 #include <errno.h>
     49 
     50 #include "test.h"
     51 #include "linux_syscall_numbers.h"
     52 
     53 char *TCID = "signal06";
     54 int TST_TOTAL = 5;
     55 
     56 #if __x86_64__
     57 
     58 #define LOOPS 10000
     59 
     60 volatile double D;
     61 volatile int FLAGE;
     62 
     63 char altstack[4096 * 10] __attribute__((aligned(4096)));
     64 
     65 void test(double d)
     66 {
     67 	int loop = 0;
     68 	int pid = getpid();
     69 
     70 	D = d;
     71 	while (D == d && loop < LOOPS) {
     72 		/* sys_tkill(pid, SIGHUP); asm to avoid save/reload
     73 		 * fp regs around c call */
     74 		asm ("" : : "a"(__NR_tkill), "D"(pid), "S"(SIGHUP));
     75 		asm ("syscall" : : : "ax");
     76 
     77 		loop++;
     78 	}
     79 
     80 	FLAGE = 1;
     81 	tst_resm(TINFO, "loop = %d", loop);
     82 
     83 	if (loop == LOOPS) {
     84 		tst_resm(TPASS, "%s call succeeded", TCID);
     85 	} else {
     86 		tst_resm(TFAIL, "Bug Reproduced!");
     87 		tst_exit();
     88 	}
     89 }
     90 
     91 void sigh(int sig LTP_ATTRIBUTE_UNUSED)
     92 {
     93 }
     94 
     95 void *tfunc(void *arg LTP_ATTRIBUTE_UNUSED)
     96 {
     97 	for (; ;) {
     98 		TEST(mprotect(altstack, sizeof(altstack), PROT_READ));
     99 		if (TEST_RETURN == -1)
    100 			tst_brkm(TBROK | TTERRNO, NULL, "mprotect failed");
    101 
    102 		TEST(mprotect(altstack, sizeof(altstack), PROT_READ|PROT_WRITE));
    103 		if (TEST_RETURN == -1)
    104 			tst_brkm(TBROK | TTERRNO, NULL, "mprotect failed");
    105 
    106 		if (FLAGE == 1)
    107 			return NULL;
    108 	}
    109 }
    110 
    111 int main(int ac, char **av)
    112 {
    113 	int i, lc;
    114 	pthread_t pt;
    115 
    116 	tst_parse_opts(ac, av, NULL, NULL);
    117 
    118 	stack_t st = {
    119 		.ss_sp = altstack,
    120 		.ss_size = sizeof(altstack),
    121 		.ss_flags = SS_ONSTACK,
    122 	};
    123 
    124 	struct sigaction sa = {
    125 		.sa_handler = sigh,
    126 	};
    127 
    128 	TEST(sigaction(SIGSEGV, &sa, NULL));
    129 	if (TEST_RETURN == -1)
    130 		tst_brkm(TBROK | TTERRNO, NULL,
    131 				"SIGSEGV signal setup failed");
    132 	sigaltstack(&st, NULL);
    133 	sa.sa_flags = SA_ONSTACK;
    134 
    135 	TEST(sigaction(SIGHUP, &sa, NULL));
    136 	if (TEST_RETURN == -1)
    137 		tst_brkm(TBROK | TTERRNO, NULL,
    138 				"SIGHUP signal setup failed");
    139 
    140 	for (lc = 0; TEST_LOOPING(lc); lc++) {
    141 		tst_count = 0;
    142 
    143 		for (i = 0; i < TST_TOTAL; i++) {
    144 			FLAGE = 0;
    145 
    146 			TEST(pthread_create(&pt, NULL, tfunc, NULL));
    147 			if (TEST_RETURN)
    148 				tst_brkm(TBROK | TRERRNO, NULL,
    149 						"pthread_create failed");
    150 
    151 			test(123.456);
    152 
    153 			TEST(pthread_join(pt, NULL));
    154 			if (TEST_RETURN)
    155 				tst_brkm(TBROK | TRERRNO, NULL,
    156 						"pthread_join failed");
    157 		}
    158 	}
    159 
    160 	tst_exit();
    161 }
    162 
    163 #else
    164 int main(void)
    165 {
    166 	tst_brkm(TCONF, NULL, "Only test on x86_64.");
    167 }
    168 #endif
    169