On 2025/11/19 1:12, Kevin Brodsky wrote:
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.
You are right,the description is unclear .
As the comment said, the calling arch code should abort the system
Which comment?
ptrace_report_syscall_entry()
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().
Yes. it is similar with the generic entry returns NO_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).
We just not need it because the original syscall_trace_enter() need use regs->syscallno as the return value, but now we return early by using NO_SYSCALL.
- 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;