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 ruanjinjie@huawei.com
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;