On Mon, Nov 26, 2018 at 08:53:35PM -0200, Rafael David Tinoco wrote: > Right now, only way for task->thread_info->syscall to be updated is if > if _TIF_SYSCALL_WORK is set in current's task thread_info->flags > (similar to what has_syscall_work() checks for arm64). > > This means that "->syscall" will only be updated if we are tracing the > syscalls through ptrace, for example. This is NOT the same behavior as > arm64, when pt_regs->syscallno is updated in the beginning of svc0 > handler for *every* syscall entry. So when was it decided that the syscall number will always be required (we need it to know how far back this has to be backported). > This patch fixes the issue since this behavior is needed for > /proc/<pid>/syscall 1st argument to be correctly updated. > > Link: https://bugs.linaro.org/show_bug.cgi?id=3783 > Cc: <stable@xxxxxxxxxxxxxxx> # v4.4 v4.9 v4.14 v4.19 > Signed-off-by: Rafael David Tinoco <rafael.tinoco@xxxxxxxxxx> > --- > arch/arm/kernel/asm-offsets.c | 1 + > arch/arm/kernel/entry-common.S | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c > index 3968d6c22455..bfe68a98e1c6 100644 > --- a/arch/arm/kernel/asm-offsets.c > +++ b/arch/arm/kernel/asm-offsets.c > @@ -64,6 +64,7 @@ int main(void) > DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp)); > DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value)); > DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate)); > + DEFINE(TI_SYSCALL, offsetof(struct thread_info, syscall)); > #ifdef CONFIG_VFP > DEFINE(TI_VFPSTATE, offsetof(struct thread_info, vfpstate)); > #ifdef CONFIG_SMP > diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S > index 0465d65d23de..557e2add4e83 100644 > --- a/arch/arm/kernel/entry-common.S > +++ b/arch/arm/kernel/entry-common.S > @@ -257,6 +257,8 @@ local_restart: > tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls? > bne __sys_trace > > + str r7, [tsk, #TI_SYSCALL] @ update thread_info->syscall "scno" is the systemcall number, not "r7". > + > invoke_syscall tbl, scno, r10, __ret_fast_syscall > > add r1, sp, #S_OFF > -- > 2.20.0.rc1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
