Split syscall_fixup into enter/exit pair of functions
* syscall.c: Create syscall_fixup_on_sysexit() which is a copy of syscall_fixup(). (trace_syscall_exiting): Call syscall_fixup_on_sysexit() instead of syscall_fixup(). Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko
parent
61526c6b1e
commit
20c41fd91d
183
syscall.c
183
syscall.c
@ -1237,7 +1237,7 @@ known_scno(struct tcb *tcp)
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return scno;
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}
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/* Called in trace_syscall() at each syscall entry and exit.
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/* Called at each syscall entry.
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* Returns:
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* 0: "ignore this ptrace stop", bail out of trace_syscall() silently.
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* 1: ok, continue in trace_syscall().
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@ -1987,6 +1987,185 @@ get_syscall_result(struct tcb *tcp)
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return 1;
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}
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/* Called at each syscall exit.
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* Returns:
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* 0: "ignore this ptrace stop", bail out of trace_syscall() silently.
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* 1: ok, continue in trace_syscall().
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* other: error, trace_syscall() should print error indicator
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* ("????" etc) and bail out.
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*/
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static int
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syscall_fixup_on_sysexit(struct tcb *tcp)
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{
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#ifdef USE_PROCFS
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int scno = known_scno(tcp);
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if (entering(tcp)) {
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if (tcp->status.PR_WHY != PR_SYSENTRY) {
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if (
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scno == SYS_fork
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#ifdef SYS_vfork
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|| scno == SYS_vfork
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#endif /* SYS_vfork */
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#ifdef SYS_fork1
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|| scno == SYS_fork1
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#endif /* SYS_fork1 */
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#ifdef SYS_forkall
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|| scno == SYS_forkall
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#endif /* SYS_forkall */
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#ifdef SYS_rfork1
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|| scno == SYS_rfork1
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#endif /* SYS_fork1 */
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#ifdef SYS_rforkall
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|| scno == SYS_rforkall
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#endif /* SYS_rforkall */
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) {
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/* We are returning in the child, fake it. */
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tcp->status.PR_WHY = PR_SYSENTRY;
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trace_syscall(tcp);
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tcp->status.PR_WHY = PR_SYSEXIT;
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}
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else {
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fprintf(stderr, "syscall: missing entry\n");
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tcp->flags |= TCB_INSYSCALL;
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}
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}
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}
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else {
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if (tcp->status.PR_WHY != PR_SYSEXIT) {
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fprintf(stderr, "syscall: missing exit\n");
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tcp->flags &= ~TCB_INSYSCALL;
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}
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}
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#endif /* USE_PROCFS */
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#ifdef SUNOS4
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if (entering(tcp)) {
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if (scno == 0) {
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fprintf(stderr, "syscall: missing entry\n");
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tcp->flags |= TCB_INSYSCALL;
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}
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}
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else {
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if (scno != 0) {
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if (debug) {
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/*
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* This happens when a signal handler
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* for a signal which interrupted a
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* a system call makes another system call.
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*/
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fprintf(stderr, "syscall: missing exit\n");
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}
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tcp->flags &= ~TCB_INSYSCALL;
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}
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}
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#endif /* SUNOS4 */
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#ifdef LINUX
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/* A common case of "not a syscall entry" is post-execve SIGTRAP */
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#if defined (I386)
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/* With PTRACE_O_TRACEEXEC, post-execve SIGTRAP is disabled.
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* Every extra ptrace call is expensive, so check EAX
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* on syscall entry only if PTRACE_O_TRACEEXEC is not enabled:
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*/
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if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
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if (upeek(tcp, 4*EAX, &eax) < 0)
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return -1;
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if (eax != -ENOSYS) {
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if (debug)
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fprintf(stderr, "not a syscall entry (eax = %ld)\n", eax);
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return 0;
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}
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}
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#elif defined (X86_64)
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if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
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if (upeek(tcp, 8*RAX, &rax) < 0)
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return -1;
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if (current_personality == 1)
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rax = (long int)(int)rax; /* sign extend from 32 bits */
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if (rax != -ENOSYS && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (rax = %ld)\n", rax);
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return 0;
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}
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}
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#elif defined (S390) || defined (S390X)
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if (upeek(tcp, PT_GPR2, &gpr2) < 0)
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return -1;
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if (syscall_mode != -ENOSYS)
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syscall_mode = tcp->scno;
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if (gpr2 != syscall_mode && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (gpr2 = %ld)\n", gpr2);
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return 0;
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}
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else if (((tcp->flags & (TCB_INSYSCALL|TCB_WAITEXECVE))
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== (TCB_INSYSCALL|TCB_WAITEXECVE))
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&& (gpr2 == -ENOSYS || gpr2 == tcp->scno)) {
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/*
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* Return from execve.
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* Fake a return value of zero. We leave the TCB_WAITEXECVE
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* flag set for the post-execve SIGTRAP to see and reset.
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*/
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gpr2 = 0;
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}
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#elif defined (POWERPC)
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# define SO_MASK 0x10000000
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if (upeek(tcp, sizeof(unsigned long)*PT_CCR, &flags) < 0)
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return -1;
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if (upeek(tcp, sizeof(unsigned long)*PT_R3, &result) < 0)
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return -1;
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if (flags & SO_MASK)
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result = -result;
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#elif defined (M68K)
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if (upeek(tcp, 4*PT_D0, &d0) < 0)
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return -1;
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if (d0 != -ENOSYS && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (d0 = %ld)\n", d0);
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return 0;
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}
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#elif defined (ARM)
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/*
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* Nothing required
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*/
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#elif defined(BFIN)
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if (upeek(tcp, PT_R0, &r0) < 0)
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return -1;
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#elif defined (HPPA)
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if (upeek(tcp, PT_GR28, &r28) < 0)
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return -1;
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#elif defined(IA64)
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if (upeek(tcp, PT_R10, &r10) < 0)
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return -1;
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if (upeek(tcp, PT_R8, &r8) < 0)
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return -1;
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if (ia32 && r8 != -ENOSYS && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (r8 = %ld)\n", r8);
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return 0;
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}
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#elif defined(CRISV10) || defined(CRISV32)
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if (upeek(tcp, 4*PT_R10, &r10) < 0)
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return -1;
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if (r10 != -ENOSYS && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (r10 = %ld)\n", r10);
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return 0;
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}
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#elif defined(MICROBLAZE)
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if (upeek(tcp, 3 * 4, &r3) < 0)
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return -1;
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if (r3 != -ENOSYS && entering(tcp)) {
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if (debug)
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fprintf(stderr, "not a syscall entry (r3 = %ld)\n", r3);
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return 0;
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}
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#endif
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#endif /* LINUX */
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return 1;
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}
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#ifdef LINUX
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/*
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* Check the syscall return value register value for whether it is
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@ -2302,7 +2481,7 @@ trace_syscall_exiting(struct tcb *tcp)
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if (res == 0)
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return res;
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if (res == 1)
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res = syscall_fixup(tcp);
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res = syscall_fixup_on_sysexit(tcp);
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if (res == 0)
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return res;
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if (res == 1)
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