On 17/11/2025 14:30, Jinjie Ruan wrote: > The generic entry handle error of ptrace_report_syscall_entry(), but > arm64 not.
This suggests that arm64 ignores the error completely, which isn't the case: no syscall will be performed, but tracing will still occur as normal. What this patch seems to be doing is to abort the _enter sequence if ptrace_report_syscall_entry() errors out. The commit title and message should be reworded accordingly. > As the comment said, the calling arch code should abort the system Which comment? > call and must prevent normal entry so no system call is > made if ptrace_report_syscall_entry() return nonzero. This is already the case since we're calling forget_syscall(). > In preparation for moving arm64 over to the generic entry code, > return early if ptrace_report_syscall_entry() encounters an error. > > Signed-off-by: Jinjie Ruan <[email protected]> > --- > arch/arm64/kernel/ptrace.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c > index 95984bbf53db..707951ad5d24 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -2317,10 +2317,10 @@ enum ptrace_syscall_dir { > PTRACE_SYSCALL_EXIT, > }; > > -static void report_syscall_enter(struct pt_regs *regs) > +static int report_syscall_enter(struct pt_regs *regs) > { > - int regno; > unsigned long saved_reg; > + int regno, ret; > > /* > * We have some ABI weirdness here in the way that we handle syscall > @@ -2342,9 +2342,13 @@ static void report_syscall_enter(struct pt_regs *regs) > saved_reg = regs->regs[regno]; > regs->regs[regno] = PTRACE_SYSCALL_ENTER; > > - if (ptrace_report_syscall_entry(regs)) > + ret = ptrace_report_syscall_entry(regs); > + if (ret) > forget_syscall(regs); The generic syscall_trace_enter() doesn't do this (i.e. setting regs->syscallno to NO_SYSCALL). Is that an oversight or do we just not need it? In principle this does have a visible effect (e.g. via REGSET_SYSTEM_CALL). - Kevin > + > regs->regs[regno] = saved_reg; > + > + return ret; > } > > static void report_syscall_exit(struct pt_regs *regs) > @@ -2374,9 +2378,11 @@ static void report_syscall_exit(struct pt_regs *regs) > > int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long > flags) > { > + int ret; > + > if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { > - report_syscall_enter(regs); > - if (flags & _TIF_SYSCALL_EMU) > + ret = report_syscall_enter(regs); > + if (ret || (flags & _TIF_SYSCALL_EMU)) > return NO_SYSCALL; > } >
