On Sat, Oct 17, 2020 at 12:07 AM <guoren@xxxxxxxxxx> wrote: > > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > It will cause warning messages: > echo function_graph > /sys/kernel/debug/tracing/current_tracer > [ 47.691397] ------------[ cut here ]------------ > [ 47.692899] WARNING: CPU: 0 PID: 11 at arch/riscv/kernel/patch.c:63 patch_insn_write+0x182/0x19a > [ 47.694483] Modules linked in: > [ 47.695754] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-11367-g1054335 #132 > [ 47.698228] epc: ffffffe000204530 ra : ffffffe00020452c sp : ffffffe0023ffc20 gp : ffffffe0013e1fe0 tp : ffffffe0023e4e00 t0 : 0000000000000000 > [ 47.701872] t1 : 000000000000000e t2 : 000000000000001b s0 : ffffffe0023ffc70 s1 : ffffffe000206850 a0 : 0000000000000000 a1 : ffffffffffffffff > [ 47.705550] a2 : 0000000000000000 a3 : ffffffe03af7c5e8 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 00000000150b02d8 > [ 47.709159] s2 : 0000000000000008 s3 : 0000000000000858 s4 : ffffffe0023ffc98 s5 : 0000000000000850 s6 : 0000000000000003 s7 : 0000000000000002 > [ 47.714135] s8 : 0000000000000004 s9 : 0000000000000001 s10: 0000000000000001 s11: 0000000000000003 t3 : ffffffffffffe000 t4 : 0000000000d86254 > [ 47.716574] t5 : 0000000000000005 t6 : 0000000000040000status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003 > [ 47.720019] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-11367-g1054335 #132 > [ 47.722074] Call Trace: > [ 47.722561] [<ffffffe000203c88>] walk_stackframe+0x0/0xc2 > [ 47.724608] [<ffffffe000b2020a>] show_stack+0x46/0x52 > [ 47.726246] [<ffffffe000b23c24>] dump_stack+0x90/0xb6 > [ 47.727672] [<ffffffe00020c9c4>] __warn+0x98/0xfa > [ 47.729131] [<ffffffe0005f4be0>] report_bug+0xaa/0x11e > [ 47.730624] [<ffffffe000203b74>] do_trap_break+0x96/0xfe > [ 47.732448] [<ffffffe000201daa>] ret_from_exception+0x0/0x14 > [ 47.734341] [<ffffffe00020452c>] patch_insn_write+0x17e/0x19a > [ 47.737235] irq event stamp: 39 > [ 47.738521] hardirqs last enabled at (39): [<ffffffe000201d0a>] _save_context+0xa2/0xe6 > [ 47.741055] hardirqs last disabled at (38): [<ffffffe0002c2404>] multi_cpu_stop+0x130/0x166 > [ 47.743551] softirqs last enabled at (0): [<ffffffe00020a4d2>] copy_process+0x430/0x1316 > [ 47.746031] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [ 47.748617] ---[ end trace 88a1054faa6524ef ]--- > > Because the path of stop_machine(__ftrace_modify_code)-> > ftrace_modify_all_code->...->patch_insn_write has no pair of > lock&unlock text_mutex, so we shouldn't put assert here. > What platform are you testing ? We are seeing a crash while enabling any of the tracers multiple times on Qemu/HiFive Unleashed. http://lists.infradead.org/pipermail/linux-riscv/2020-October/002354.html As per the thread, Zong agreed to take a look into that. @Zong Li : Do you have any update regarding the ftrace issue. > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > --- > arch/riscv/kernel/patch.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c > index 0b55287..2ee5063 100644 > --- a/arch/riscv/kernel/patch.c > +++ b/arch/riscv/kernel/patch.c > @@ -55,13 +55,6 @@ static int patch_insn_write(void *addr, const void *insn, size_t len) > bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE; > int ret; > > - /* > - * Before reaching here, it was expected to lock the text_mutex > - * already, so we don't need to give another lock here and could > - * ensure that it was safe between each cores. > - */ > - lockdep_assert_held(&text_mutex); > - > if (across_pages) > patch_map(addr + len, FIX_TEXT_POKE1); > > -- > 2.7.4 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-riscv -- Regards, Atish
