Messages in this thread | | | From | Atish Patra <> | Date | Sat, 18 Sep 2021 19:35:26 -0700 | Subject | Re: [PATCH] riscv: Flush current cpu icache before other cpus |
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On Sat, Sep 18, 2021 at 9:03 AM Alexandre Ghiti <alex@ghiti.fr> wrote: > > On SiFive Unmatched, I recently fell onto the following BUG when booting: > > [ 0.000000] ftrace: allocating 36610 entries in 144 pages > [ 0.000000] Oops - illegal instruction [#1] > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5 > [ 0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT) > [ 0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae > [ 0.000000] ra : __sbi_rfence_v02+0xc8/0x10a > [ 0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10 > [ 0.000000] gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000 > [ 0.000000] t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60 > [ 0.000000] s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10 > [ 0.000000] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 > [ 0.000000] a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43 > [ 0.000000] s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000 > [ 0.000000] s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001 > [ 0.000000] s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000 > [ 0.000000] s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008 > [ 0.000000] t5 : ffffffcf04000808 t6 : ffffffe3ffddf188 > [ 0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002 > [ 0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae > [ 0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26 > [ 0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a > [ 0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32 > [ 0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c > [ 0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360 > [ 0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130 > [ 0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6 > [ 0.000000] ---[ end trace f67eb9af4d8d492b ]--- > [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! > [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- > > While ftrace is looping over a list of addresses to patch, it always failed > when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the > backtrace, the illegal instruction is encountered in this same function. > However, patch_text_nosync, after patching the instructions, calls > flush_icache_range. But looking at what happens in this function: > > flush_icache_range -> flush_icache_all > -> sbi_remote_fence_i > -> __sbi_rfence_v02 > -> riscv_cpuid_to_hartid_mask > > The icache and dcache of the current cpu are never synchronized between the > patching of riscv_cpuid_to_hartid_mask and calling this same function. > > So fix this by flushing the current cpu's icache before asking for the other > cpus to do the same. >
Is this the same bugs described in this thread ?
http://lkml.iu.edu/hypermail/linux/kernel/2108.1/05465.html
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > --- > arch/riscv/mm/cacheflush.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c > index 094118663285..89f81067e09e 100644 > --- a/arch/riscv/mm/cacheflush.c > +++ b/arch/riscv/mm/cacheflush.c > @@ -16,6 +16,8 @@ static void ipi_remote_fence_i(void *info) > > void flush_icache_all(void) > { > + local_flush_icache_all(); > + > if (IS_ENABLED(CONFIG_RISCV_SBI)) > sbi_remote_fence_i(NULL); > else > -- > 2.30.2 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
-- Regards, Atish
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