<[email protected]> 於 2020年6月23日 週二 下午5:52寫道： > > From: Guo Ren <[email protected]> > > For linux-5.8-rc1, enable ftrace of riscv will cause boot panic: > > [ 2.388980] Run /sbin/init as init process > [ 2.529938] init[39]: unhandled signal 4 code 0x1 at 0x0000003ff449e000 > [ 2.531078] CPU: 0 PID: 39 Comm: init Not tainted 5.8.0-rc1-dirty #13 > [ 2.532719] epc: 0000003ff449e000 ra : 0000003ff449e954 sp : > 0000003fffedb900 > [ 2.534005] gp : 00000000000e8528 tp : 0000003ff449d800 t0 : > 000000000000001e > [ 2.534965] t1 : 000000000000000a t2 : 0000003fffedb89e s0 : > 0000003fffedb920 > [ 2.536279] s1 : 0000003fffedb940 a0 : 0000003ff43d4b2c a1 : > 0000000000000000 > [ 2.537334] a2 : 0000000000000001 a3 : 0000000000000000 a4 : > fffffffffbad8000 > [ 2.538466] a5 : 0000003ff449e93a a6 : 0000000000000000 a7 : > 0000000000000000 > [ 2.539511] s2 : 0000000000000000 s3 : 0000003ff448412c s4 : > 0000000000000010 > [ 2.541260] s5 : 0000000000000016 s6 : 00000000000d0a30 s7 : > 0000003fffedba70 > [ 2.542152] s8 : 0000000000000000 s9 : 0000000000000000 s10: > 0000003fffedb960 > [ 2.543335] s11: 0000000000000000 t3 : 0000000000000000 t4 : > 0000003fffedb8a0 > [ 2.544471] t5 : 0000000000000000 t6 : 0000000000000000 > [ 2.545730] status: 0000000000004020 badaddr: 00000000464c457f cause: > 0000000000000002 > [ 2.549867] Kernel panic - not syncing: Attempted to kill init! > exitcode=0x00000004 > [ 2.551267] CPU: 0 PID: 1 Comm: init Not tainted 5.8.0-rc1-dirty #13 > [ 2.552061] Call Trace: > [ 2.552626] [<ffffffe00020374a>] walk_stackframe+0x0/0xc4 > [ 2.553486] [<ffffffe0002039f4>] show_stack+0x40/0x4c > [ 2.553995] [<ffffffe00054a6ae>] dump_stack+0x7a/0x98 > [ 2.554615] [<ffffffe00020b9b8>] panic+0x114/0x2f4 > [ 2.555395] [<ffffffe00020ebd6>] do_exit+0x89c/0x8c2 > [ 2.555949] [<ffffffe00020f930>] do_group_exit+0x3a/0x90 > [ 2.556715] [<ffffffe000219e08>] get_signal+0xe2/0x6e6 > [ 2.557388] [<ffffffe000202d72>] do_notify_resume+0x6a/0x37a > [ 2.558089] [<ffffffe000201c16>] ret_from_exception+0x0/0xc > > "ra:0x3ff449e954" is the return address of "call _mcount" in the > prologue of __vdso_gettimeofday(). Without proper relocate, pc jmp > to 0x0000003ff449e000 (vdso map base) with a illegal instruction > trap. > > The solution comes from arch/arm64/kernel/vdso/Makefile: > > CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) > > - CC_FLAGS_SCS is ShadowCallStack feature in Clang and only > implemented for arm64, no use for riscv. > > The bug comes from the following commit: > > ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the > time-related functions") > > Signed-off-by: Guo Ren <[email protected]> > Cc: Vincent Chen <[email protected]> > Cc: Atish Patra <[email protected]> > Cc: Palmer Dabbelt <[email protected]> > Cc: Alan Kao <[email protected]> > Cc: Greentime Hu <[email protected]> > --- > arch/riscv/kernel/vdso/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile > index 38ba55b..3079935 100644 > --- a/arch/riscv/kernel/vdso/Makefile > +++ b/arch/riscv/kernel/vdso/Makefile > @@ -27,6 +27,9 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) > obj-y += vdso.o vdso-syms.o > CPPFLAGS_vdso.lds += -P -C -U$(ARCH) > > +# Disable -pg to prevent insert call site > +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os > + > # Disable gcov profiling for VDSO code > GCOV_PROFILE := n >
Thank you, Guo. I encounter the same bug in v5.8-rc2. This patch works. Tested-by: Greentime Hu <[email protected]>
