On Sat, 11 Mar 2023 at 18:32, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: > > > > On 3/10/2023 4:13 AM, Álvaro Fernández Rojas wrote: > > arch_sync_dma_for_cpu_all() causes kernel panics on BCM6358 with EHCI/OHCI: > > [ 3.881739] usb 1-1: new high-speed USB device number 2 using ehci-platform > > [ 3.895011] Reserved instruction in kernel code[#1]: > > [ 3.900113] CPU: 0 PID: 1 Comm: init Not tainted 5.10.16 #0 > > [ 3.905829] $ 0 : 00000000 10008700 00000000 77d94060 > > [ 3.911238] $ 4 : 7fd1f088 00000000 81431cac 81431ca0 > > [ 3.916641] $ 8 : 00000000 ffffefff 8075cd34 00000000 > > [ 3.922043] $12 : 806f8d40 f3e812b7 00000000 000d9aaa > > [ 3.927446] $16 : 7fd1f068 7fd1f080 7ff559b8 81428470 > > [ 3.932848] $20 : 00000000 00000000 55590000 77d70000 > > [ 3.938251] $24 : 00000018 00000010 > > [ 3.943655] $28 : 81430000 81431e60 81431f28 800157fc > > [ 3.949058] Hi : 00000000 > > [ 3.952013] Lo : 00000000 > > [ 3.955019] epc : 80015808 setup_sigcontext+0x54/0x24c > > [ 3.960464] ra : 800157fc setup_sigcontext+0x48/0x24c > > [ 3.965913] Status: 10008703 KERNEL EXL IE > > [ 3.970216] Cause : 00800028 (ExcCode 0a) > > [ 3.974340] PrId : 0002a010 (Broadcom BMIPS4350) > > [ 3.979170] Modules linked in: ohci_platform ohci_hcd fsl_mph_dr_of ehci_platform ehci_fsl ehci_hcd gpio_button_hotplug usbcore nls_base usb_common > > [ 3.992907] Process init (pid: 1, threadinfo=(ptrval), task=(ptrval), tls=77e22ec8) > > [ 4.000776] Stack : 81431ef4 7fd1f080 81431f28 81428470 7fd1f068 81431edc 7ff559b8 81428470 > > [ 4.009467] 81431f28 7fd1f080 55590000 77d70000 77d5498c 80015c70 806f0000 8063ae74 > > [ 4.018149] 08100002 81431f28 0000000a 08100002 81431f28 0000000a 77d6b418 00000003 > > [ 4.026831] ffffffff 80016414 80080734 81431ecc 81431ecc 00000001 00000000 04000000 > > [ 4.035512] 77d54874 00000000 00000000 00000000 00000000 00000012 00000002 00000000 > > [ 4.044196] ... > > [ 4.046706] Call Trace: > > [ 4.049238] [<80015808>] setup_sigcontext+0x54/0x24c > > [ 4.054356] [<80015c70>] setup_frame+0xdc/0x124 > > [ 4.059015] [<80016414>] do_notify_resume+0x1dc/0x288 > > [ 4.064207] [<80011b50>] work_notifysig+0x10/0x18 > > [ 4.069036] > > [ 4.070538] Code: 8fc300b4 00001025 26240008 <ac820000> ac830004 3c048063 0c0228aa 24846a00 26240010 > > [ 4.080686] > > [ 4.082517] ---[ end trace 22a8edb41f5f983b ]--- > > [ 4.087374] Kernel panic - not syncing: Fatal exception > > [ 4.092753] Rebooting in 1 seconds.. > > Did you pinpoint which specific instruction within > arch_sync_dma_for_cpu_all() is causing the reserved instruction exception? It's setup_sigcontext(), not arch_sync_dma_for_cpu_all() that's causing the exception ;-) Hand decoding the Code gives me lw $1, 0xb4($fp) or $v0, 0, 0 addiu $a0, $s1, 8 sw $v0, 0($a0) <- the code in brackets, so I guess EPC? sw $v1, 4($a0) which I assume is this part: err |= __put_user(regs->cp0_epc, &sc->sc_pc); (0xb4 is the offset of cp0_epc, 0x8 the offset of sc_pc) One thing I see is that we do the RAC flush for BMIPS3300, 4350 and 4380, but only initialize it for 3300 [1], but leave it at whatever state the bootloader did for the other ones. Maybe it has some invalid config in (that particuar?) 6358 that triggers issues later on after a flush? E.g. the flush puts it in an error state, and the next time something triggers a prefetch(write?) (by trying to access userspace) it generates an error exception. Just spit balling though. [1] https://elixir.bootlin.com/linux/latest/source/arch/mips/kernel/smp-bmips.c#L587 Jonas
