• Zong Li's avatar
    clocksource: riscv: add notrace to riscv_sched_clock · 9d05c18e
    Zong Li authored
    When enabling ftrace graph tracer, it gets the tracing clock in
    ftrace_push_return_trace().  Eventually, it invokes riscv_sched_clock()
    to get the clock value.  If riscv_sched_clock() isn't marked with
    'notrace', it will call ftrace_push_return_trace() and cause infinite
    loop.
    
    The result of failure as follow:
    
    command: echo function_graph >current_tracer
    [   46.176787] Unable to handle kernel paging request at virtual address ffffffe04fb38c48
    [   46.177309] Oops [#1]
    [   46.177478] Modules linked in:
    [   46.177770] CPU: 0 PID: 256 Comm: $d Not tainted 5.5.0-rc1 #47
    [   46.177981] epc: ffffffe00035e59a ra : ffffffe00035e57e sp : ffffffe03a7569b0
    [   46.178216]  gp : ffffffe000d29b90 tp : ffffffe03a756180 t0 : ffffffe03a756968
    [   46.178430]  t1 : ffffffe00087f408 t2 : ffffffe03a7569a0 s0 : ffffffe03a7569f0
    [   46.178643]  s1 : ffffffe00087f408 a0 : 0000000ac054cda4 a1 : 000000000087f411
    [   46.178856]  a2 : 0000000ac054cda4 a3 : 0000000000373ca0 a4 : ffffffe04fb38c48
    [   46.179099]  a5 : 00000000153e22a8 a6 : 00000000005522ff a7 : 0000000000000005
    [   46.179338]  s2 : ffffffe03a756a90 s3 : ffffffe00032811c s4 : ffffffe03a756a58
    [   46.179570]  s5 : ffffffe000d29fe0 s6 : 0000000000000001 s7 : 0000000000000003
    [   46.179809]  s8 : 0000000000000003 s9 : 0000000000000002 s10: 0000000000000004
    [   46.180053]  s11: 0000000000000000 t3 : 0000003fc815749c t4 : 00000000000efc90
    [   46.180293]  t5 : ffffffe000d29658 t6 : 0000000000040000
    [   46.180482] status: 0000000000000100 badaddr: ffffffe04fb38c48 cause: 000000000000000f
    Signed-off-by: default avatarZong Li <zong.li@sifive.com>
    Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    [paul.walmsley@sifive.com: cleaned up patch description]
    Fixes: 92e0d143 ("clocksource/drivers/riscv_timer: Provide the sched_clock")
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarPaul Walmsley <paul.walmsley@sifive.com>
    9d05c18e
timer-riscv.c 3.49 KB