@@ -89,6 +89,16 @@ ENTRY(system_call)
jbsr %a0@
movel %d0,%sp@(PT_OFF_D0) /* save the return value*/
+ /* descriptors reserved by the syscall are committed in syscall_trace_leave */
+ getthreadinfo
+ btst #(TIF_FD_SLOTS%8),%a2@(TINFO_FLAGS+(31-TIF_FD_SLOTS)/8)
+ jeq ret_from_exception
+ subql #4,%sp /* dummy return address */
+ SAVE_SWITCH_STACK
+ jbsr syscall_trace_leave
+ RESTORE_SWITCH_STACK
+ addql #4,%sp
+
ret_from_exception:
btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel*/
jeq Luser_return /* if so, skip resched, signals*/
@@ -78,6 +78,18 @@ ENTRY(system_call)
movel %d3,%a0
jbsr %a0@
movel %d0,%sp@(PT_OFF_D0) /* save the return value */
+
+ /* descriptors reserved by the syscall are committed in syscall_trace_leave */
+ movel %sp,%d2 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d2 /* at start of kernel stack */
+ movel %d2,%a0
+ btst #(TIF_FD_SLOTS%8),%a0@(TINFO_FLAGS+(31-TIF_FD_SLOTS)/8)
+ jeq ret_from_exception
+ subql #4,%sp /* dummy return address */
+ SAVE_SWITCH_STACK
+ jbsr syscall_trace_leave
+ RESTORE_SWITCH_STACK
+ addql #4,%sp
jra ret_from_exception
1:
movel #-ENOSYS,%d2 /* strace needs -ENOSYS in PT_OFF_D0 */
@@ -62,6 +62,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_NOTIFY_RESUME 5 /* callback before returning to user */
#define TIF_SIGPENDING 6 /* signal pending */
#define TIF_NEED_RESCHED 7 /* rescheduling necessary */
+#define TIF_FD_SLOTS 12 /* syscall prepared descriptors */
#define TIF_SECCOMP 13 /* seccomp syscall filtering active */
#define TIF_DELAYED_TRACE 14 /* single step a syscall */
#define TIF_SYSCALL_TRACE 15 /* syscall trace active */
@@ -71,6 +72,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
+#define _TIF_FD_SLOTS (1 << TIF_FD_SLOTS)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_DELAYED_TRACE (1 << TIF_DELAYED_TRACE)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
@@ -229,6 +229,8 @@ ret_from_syscall:
syscall_exit_work:
btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
bnes 1b | if so, skip resched, signals
+ btst #4,%a1@(TINFO_FLAGS+2) | TIF_FD_SLOTS: commit descriptors
+ jne do_trace_exit
lslw #1,%d0
jcs do_trace_exit
jmi do_delayed_trace
@@ -11,6 +11,7 @@
*/
#include <linux/kernel.h>
+#include <linux/file.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
@@ -289,6 +290,8 @@ asmlinkage int syscall_trace_enter(void)
asmlinkage void syscall_trace_leave(void)
{
+ if (test_thread_flag(TIF_FD_SLOTS))
+ fd_slots_commit(task_pt_regs(current));
if (test_thread_flag(TIF_SYSCALL_TRACE))
ptrace_report_syscall_exit(task_pt_regs(current), 0);
}
Add TIF_FD_SLOTS and test it on the untraced return from a system call in all three entry paths. A task that reserved descriptors calls syscall_trace_leave(), which commits them before the ptrace exit stop. The traced paths already end up there. Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> --- arch/m68k/68000/entry.S | 10 ++++++++++ arch/m68k/coldfire/entry.S | 12 ++++++++++++ arch/m68k/include/asm/thread_info.h | 2 ++ arch/m68k/kernel/entry.S | 2 ++ arch/m68k/kernel/ptrace.c | 3 +++ 5 files changed, 29 insertions(+)