[uml-devel] [PATCH 4/5] um: Handle tracehook_report_syscall_entry() result

[Richard Weinberger]

tracehook_report_syscall_entry() is allowed to fail,
in case of failure we have to abort the current syscall.

Signed-off-by: Richard Weinberger <rich...@nod.at>
---
 arch/um/include/asm/ptrace-generic.h | 2 +-
 arch/um/kernel/ptrace.c              | 6 +++---
 arch/um/kernel/skas/syscall.c        | 6 +++++-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/um/include/asm/ptrace-generic.h 
b/arch/um/include/asm/ptrace-generic.h
index cb9b3c4..283480a 100644
--- a/arch/um/include/asm/ptrace-generic.h
+++ b/arch/um/include/asm/ptrace-generic.h
@@ -37,7 +37,7 @@ extern int putreg(struct task_struct *child, int regno, 
unsigned long value);
 
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
-extern void syscall_trace_enter(struct pt_regs *regs);
+extern int syscall_trace_enter(struct pt_regs *regs);
 extern void syscall_trace_leave(struct pt_regs *regs);
 
 #endif
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index 174ee50..cac2ea0 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -131,7 +131,7 @@ static void send_sigtrap(struct task_struct *tsk, struct 
uml_pt_regs *regs,
  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
  */
-void syscall_trace_enter(struct pt_regs *regs)
+int syscall_trace_enter(struct pt_regs *regs)
 {
        audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
                            UPT_SYSCALL_ARG1(&regs->regs),
@@ -140,9 +140,9 @@ void syscall_trace_enter(struct pt_regs *regs)
                            UPT_SYSCALL_ARG4(&regs->regs));
 
        if (!test_thread_flag(TIF_SYSCALL_TRACE))
-               return;
+               return 0;
 
-       tracehook_report_syscall_entry(regs);
+       return tracehook_report_syscall_entry(regs);
 }
 
 void syscall_trace_leave(struct pt_regs *regs)
diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c
index c0681e0..d9ec006 100644
--- a/arch/um/kernel/skas/syscall.c
+++ b/arch/um/kernel/skas/syscall.c
@@ -18,7 +18,10 @@ void handle_syscall(struct uml_pt_regs *r)
        long result;
        int syscall;
 
-       syscall_trace_enter(regs);
+       if (syscall_trace_enter(regs)) {
+               result = -ENOSYS;
+               goto out;
+       }
 
        /*
         * This should go in the declaration of syscall, but when I do that,
@@ -34,6 +37,7 @@ void handle_syscall(struct uml_pt_regs *r)
                result = -ENOSYS;
        else result = EXECUTE_SYSCALL(syscall, regs);
 
+out:
        PT_REGS_SET_SYSCALL_RETURN(regs, result);
 
        syscall_trace_leave(regs);
-- 
1.8.4.5


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