Messages in this thread | | | Date | Tue, 10 May 2022 11:59:48 +0100 | From | Will Deacon <> | Subject | Re: [RFC PATCH v1 1/1] arm64: Forget syscall if different from execve*() |
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On Mon, May 09, 2022 at 04:19:57PM +0100, Francis Laniel wrote: > This patch enables exeve*() to be traced by syscalls:sys_exit_execve > tracepoint. > Previously, calling forget_syscall() would set syscall to -1, which impedes > this tracepoint to prints its information. > So, this patch makes call to forget_syscall() conditional by only calling > it when syscall number is not execve() or execveat(). > > Signed-off-by: Francis Laniel <flaniel@linux.microsoft.com> > --- > arch/arm64/include/asm/processor.h | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h > index 73e38d9a540c..e12ceb363d6a 100644 > --- a/arch/arm64/include/asm/processor.h > +++ b/arch/arm64/include/asm/processor.h > @@ -34,6 +34,8 @@ > > #include <vdso/processor.h> > > +#include <asm-generic/unistd.h> > + > #include <asm/alternative.h> > #include <asm/cpufeature.h> > #include <asm/hw_breakpoint.h> > @@ -250,8 +252,12 @@ void tls_preserve_current_state(void); > > static inline void start_thread_common(struct pt_regs *regs, unsigned long pc) > { > + s32 previous_syscall = regs->syscallno; > memset(regs, 0, sizeof(*regs)); > - forget_syscall(regs); > + if (previous_syscall == __NR_execve || previous_syscall == __NR_execveat) > + regs->syscallno = previous_syscall; > + else > + forget_syscall(regs);
Hmm, this really looks like a bodge and it doesn't handle the compat case either.
How do other architectures handle this?
Will
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