On 2021/11/25 22:34, Martin Kennedy wrote:
Hi there,
Yes, I can test this patch.
I have added it to my tree and removed the reversion, and can confirm that the second CPU comes up correctly now.
Martin
Thank you very much for your report and testing, I'll send a patch later
Thanks Xiaoming Ni
On Thu, Nov 25, 2021 at 2:23 AM Xiaoming Ni nixiaoming@huawei.com wrote:
On 2021/11/25 12:20, Martin Kennedy wrote:
Hi there,
I have bisected OpenWrt master, and then the Linux kernel down to this change, to confirm that this change causes a kernel panic on my P1020RDB-based, dual-core Aerohive HiveAP 370, at initialization of the second CPU:
: [ 0.000000] Linux version 5.10.80 (labby@lobon) (powerpc-openwrt-linux-musl-gcc (OpenWrt GCC 11.2.0 r18111+1-ebb6f9287e) 11.2.0, GNU ld (GNU Binutils) 2.37) #0 SMP Thu Nov 25 02:49:35 2021 [ 0.000000] Using P1020 RDB machine description : [ 0.627233] smp: Bringing up secondary CPUs ... [ 0.681659] kernel tried to execute user page (0) - exploit attempt? (uid: 0) [ 0.766618] BUG: Unable to handle kernel instruction fetch (NULL pointer?) [ 0.848899] Faulting instruction address: 0x00000000 [ 0.908273] Oops: Kernel access of bad area, sig: 11 [#1] [ 0.972851] BE PAGE_SIZE=4K SMP NR_CPUS=2 P1020 RDB [ 1.031179] Modules linked in: [ 1.067640] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.80 #0 [ 1.139507] NIP: 00000000 LR: c0021d2c CTR: 00000000 [ 1.199921] REGS: c1051cf0 TRAP: 0400 Not tainted (5.10.80) [ 1.269705] MSR: 00021000 <CE,ME> CR: 84020202 XER: 00000000 [ 1.340534] [ 1.340534] GPR00: c0021cb8 c1051da8 c1048000 00000001 00029000 00000000 00000001 00000000 [ 1.340534] GPR08: 00000001 00000000 c08b0000 00000040 22000208 00000000 c00032c4 00000000 [ 1.340534] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00029000 00000001 [ 1.340534] GPR24: 1ffff240 20000000 dffff240 c080a1f4 00000001 c08ae0a8 00000001 dffff240 [ 1.758220] NIP [00000000] 0x0 [ 1.794688] LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568 [ 1.856126] Call Trace: [ 1.885295] [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable) [ 1.968633] [c1051de8] [c0011460] __cpu_up+0xc0/0x228 [ 2.029038] [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224 [ 2.092572] [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c [ 2.164443] [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8 [ 2.236326] [c1051eb8] [c07e67bc] smp_init+0x30/0x78 [ 2.295698] [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8 [ 2.369641] [c1051f18] [c00032d8] kernel_init+0x14/0x124 [ 2.433176] [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c [ 2.507125] Instruction dump: [ 2.542541] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 2.635242] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 2.727952] ---[ end trace 9b796a4bafb6bc14 ]--- [ 2.783149] [ 3.800879] Kernel panic - not syncing: Fatal exception [ 3.862353] Rebooting in 1 seconds.. [ 5.905097] System Halted, OK to turn off power
Without this patch, the kernel no longer panics:
[ 0.627232] smp: Bringing up secondary CPUs ... [ 0.681857] smp: Brought up 1 node, 2 CPUs
Here is the kernel configuration for this built kernel: https://git.openwrt.org/?p=openwrt/openwrt.git%3Ba=blob_plain%3Bf=target/lin...
In case a force-push is needed for the source repository (https://github.com/Hurricos/openwrt/commit/ad19bdfc77d60ee1c52b41bb4345fdd02...), here is the device tree for this board: https://paste.c-net.org/TrousersSliced
Martin .
When CONFIG_FSL_PMC is set to n, cpu_up_prepare is not assigned to mpc85xx_pm_ops. I suspect that this is the cause of the current null pointer access. I do not have the corresponding board test environment. Can you help me to test whether the following patch solves the problem?
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index 83f4a6389a28..d7081e9af65c 100644 --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -220,7 +220,7 @@ static int smp_85xx_start_cpu(int cpu) local_irq_save(flags); hard_irq_disable();
- if (qoriq_pm_ops)
if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) qoriq_pm_ops->cpu_up_prepare(cpu);
/* if cpu is not spinning, reset it */@@ -292,7 +292,7 @@ static int smp_85xx_kick_cpu(int nr) booting_thread_hwid = cpu_thread_in_core(nr); primary = cpu_first_thread_sibling(nr);
if (qoriq_pm_ops)
if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) qoriq_pm_ops->cpu_up_prepare(nr); /*.