Hi, When I built an allmodconfig kernel for arm64, and boot that in qemu guest I see the following issues:
[...] [ 10.451561][ T1] Testing tracer function: PASSED [ 33.087895][ T1] Testing dynamic ftrace: .. filter did not filter .. FAILED! [ 51.127094][ T1] ------------[ cut here ]------------ [ 51.132387][ T1] WARNING: CPU: 0 PID: 1 at kernel/trace/trace.c:1814 run_tracer_selftest+0x314/0x40c [ 51.140805][ T1] Modules linked in: [ 51.145398][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3-next-20200703-00004-g8cd4bc531754 #1 [ 51.154146][ T1] Hardware name: linux,dummy-virt (DT) [ 51.159536][ T1] pstate: 80400005 (Nzcv daif +PAN -UAO BTYPE=--) [ 51.165711][ T1] pc : run_tracer_selftest+0x314/0x40c [ 51.171167][ T1] lr : run_tracer_selftest+0x308/0x40c [ 51.176475][ T1] sp : ffff000069c07c40 [ 51.180855][ T1] x29: ffff000069c07c40 x28: ffffa00015e80320 [ 51.187187][ T1] x27: ffffa00013e074a0 x26: ffffa000150f22ee [ 51.193520][ T1] x25: ffffa000125b35a0 x24: ffffa00013f6a000 [ 51.199868][ T1] x23: ffffa00013f6adc0 x22: 00000000ffffffff [ 51.206225][ T1] x21: ffffa000150f2250 x20: ffffa00015e801c0 [ 51.212582][ T1] x19: ffffa00015e7fa80 x18: 0000000000002750 [ 51.218887][ T1] x17: 00000000000014c0 x16: 00000000000016f0 [ 51.225229][ T1] x15: 00000000000014f8 x14: ffffa0001000a3c8 [ 51.231584][ T1] x13: ffffa000124a5fb8 x12: ffff80000d494822 [ 51.237935][ T1] x11: 1fffe0000d494821 x10: ffff80000d494821 [ 51.244293][ T1] x9 : ffffa000101763b0 x8 : ffff000069c077d7 [ 51.250704][ T1] x7 : 0000000000000001 x6 : ffff000069c077d0 [ 51.257060][ T1] x5 : ffff00006a7fc040 x4 : 0000000000000000 [ 51.263423][ T1] x3 : ffffa00010211118 x2 : 8af0509000018b00 [ 51.269757][ T1] x1 : 0000000000000000 x0 : 0000000000000001 [ 51.276084][ T1] Call trace: [ 51.279934][ T1] run_tracer_selftest+0x314/0x40c [ 51.285174][ T1] init_trace_selftests+0x110/0x31c [ 51.290391][ T1] do_one_initcall+0x410/0x960 [ 51.295315][ T1] kernel_init_freeable+0x430/0x4f0 [ 51.300595][ T1] kernel_init+0x20/0x1d8 [ 51.305180][ T1] ret_from_fork+0x10/0x18 [ 51.309741][ T1] irq event stamp: 1401832 [ 51.314399][ T1] hardirqs last enabled at (1401831): [<ffffa0001020d10c>] console_unlock+0xc04/0xd10 [ 51.322973][ T1] hardirqs last disabled at (1401832): [<ffffa00010050fe4>] debug_exception_enter+0xbc/0x200 [ 51.331993][ T1] softirqs last enabled at (1401828): [<ffffa000100023a4>] __do_softirq+0x95c/0x9f8 [ 51.340490][ T1] softirqs last disabled at (1401821): [<ffffa0001010f7d0>] irq_exit+0x118/0x198 [ 51.348717][ T1] _warn_unseeded_randomness: 5 callbacks suppressed [ 51.349263][ T1] random: get_random_bytes called from print_oops_end_marker+0x48/0x80 with crng_init=0 [ 51.350502][ T1] ---[ end trace c566e8a71c933d3c ]--- [...] [40709.672335][ C0] pool 2: cpus=0 flags=0x5 nice=0 hung=3s workers=3 manager: 1455 [40739.960593][ T26] INFO: lockdep is turned off. [40775.312499][ T26] Kernel panic - not syncing: hung_task: blocked tasks [40775.341521][ T26] CPU: 0 PID: 26 Comm: khungtaskd Tainted: G W 5.8.0-rc3-next-20200703-00004-g8cd4bc531754 #1 [40775.352848][ T26] Hardware name: linux,dummy-virt (DT) [40775.359304][ T26] Call trace: [40775.364148][ T26] dump_backtrace+0x0/0x418 [40775.369918][ T26] show_stack+0x34/0x48 [40775.375468][ T26] dump_stack+0x1f4/0x2b0 [40775.381136][ T26] panic+0x2dc/0x6ec [40775.386430][ T26] watchdog+0x1400/0x1460 [40775.392103][ T26] kthread+0x23c/0x250 [40775.397548][ T26] ret_from_fork+0x10/0x18 [40775.407039][ T26] Kernel Offset: disabled [40775.412634][ T26] CPU features: 0x240002,20002004 [40775.418751][ T26] Memory Limit: none [40775.425823][ T26] ---[ end Kernel panic - not syncing: hung_task: blocked tasks ]--- The full log can be found here [1]. Without this patch for 'trace_selftest_dynamic' for instance, CC_FLAGS_FTRACE was removed from kernel/trace/*, and then added back to kernel/trace/trace_selftest_dynamic. While with this patch it looks like we add the flag (even though it is already there), and then removes the flag for all files in kernel/trace/* . Cheers, Anders [1] https://people.linaro.org/~anders.roxell/output-next-20200703.log On Tue, 30 Jun 2020 at 04:09, Masahiro Yamada <masahi...@kernel.org> wrote: > > On Mon, Jun 29, 2020 at 2:55 PM Michael Ellerman <m...@ellerman.id.au> wrote: > > > > Masahiro Yamada <masahi...@kernel.org> writes: > > > CFLAGS_REMOVE_<file>.o works per object, that is, there is no > > > convenient way to filter out flags for every object in a directory. > > > > > > Add ccflags-remove-y and asflags-remove-y to make it easily. > > > > > > Use ccflags-remove-y to clean up some Makefiles. > > > > > > Suggested-by: Sami Tolvanen <samitolva...@google.com> > > > Signed-off-by: Masahiro Yamada <masahi...@kernel.org> > > > --- > > > > > > arch/arm/boot/compressed/Makefile | 6 +----- > > > arch/powerpc/xmon/Makefile | 3 +-- > > > arch/sh/boot/compressed/Makefile | 5 +---- > > > kernel/trace/Makefile | 4 ++-- > > > lib/Makefile | 5 +---- > > > scripts/Makefile.lib | 4 ++-- > > > 6 files changed, 8 insertions(+), 19 deletions(-) > > > > > > diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile > > > index 89c76ca35640..55cbcdd88ac0 100644 > > > --- a/arch/powerpc/xmon/Makefile > > > +++ b/arch/powerpc/xmon/Makefile > > > @@ -7,8 +7,7 @@ UBSAN_SANITIZE := n > > > KASAN_SANITIZE := n > > > > > > # Disable ftrace for the entire directory > > > -ORIG_CFLAGS := $(KBUILD_CFLAGS) > > > -KBUILD_CFLAGS = $(subst $(CC_FLAGS_FTRACE),,$(ORIG_CFLAGS)) > > > +ccflags-remove-y += $(CC_FLAGS_FTRACE) > > > > This could be: > > > > ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) > > > > Similar to kernel/trace/Makefile below. > > > I fixed it up, and applied to linux-kbuild. > Thanks. > > > > I don't mind though. > > > > Acked-by: Michael Ellerman <m...@ellerman.id.au> (powerpc) > > > > cheers > > > > > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > > > index 6575bb0a0434..7492844a8b1b 100644 > > > --- a/kernel/trace/Makefile > > > +++ b/kernel/trace/Makefile > > > @@ -2,9 +2,9 @@ > > > > > > # Do not instrument the tracer itself: > > > > > > +ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) > > > + > > > ifdef CONFIG_FUNCTION_TRACER > > > -ORIG_CFLAGS := $(KBUILD_CFLAGS) > > > -KBUILD_CFLAGS = $(subst $(CC_FLAGS_FTRACE),,$(ORIG_CFLAGS)) > > > > > > # Avoid recursion due to instrumentation. > > > KCSAN_SANITIZE := n > > > > -- > Best Regards > Masahiro Yamada
