Excerpts from Christophe Leroy's message of August 4, 2021 11:28 pm: > > > Le 04/08/2021 à 13:36, Nicholas Piggin a écrit : >> Excerpts from Christophe Leroy's message of August 4, 2021 4:21 pm: >>> Hi Nic, >>> >>> I think I'll need your help on that one. >>> >>> Le 04/08/2021 à 08:07, Christophe Leroy a écrit : >>>> >>>> >>>> Le 04/08/2021 à 06:04, Finn Thain a écrit : >> >> Hi Finn! >> >>>>> On Tue, 3 Aug 2021, Christophe Leroy wrote: >>>>> >>> ... >>>>> >>>>> ------------[ cut here ]------------ >>>>> kernel BUG at arch/powerpc/kernel/interrupt.c:49! >>>>> Oops: Exception in kernel mode, sig: 5 [#1] >>>>> BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac >>>>> Modules linked in: >>>>> CPU: 0 PID: 1859 Comm: xfce4-session Not tainted 5.13.0-pmac-VMAP #10 >>>>> NIP: c0011474 LR: c0011464 CTR: 00000000 >>>>> REGS: e2f75e40 TRAP: 0700 Not tainted (5.13.0-pmac-VMAP) >>>>> MSR: 00021032 <ME,IR,DR,RI> CR: 2400446c XER: 20000000 >>>>> >>>>> GPR00: c001604c e2f75f00 ca284a60 00000000 00000000 a5205eb0 00000008 >>>>> 00000020 >>>>> GPR08: ffffffc0 00000001 501200d9 ce030005 ca285010 00c1f778 00000000 >>>>> 00000000 >>>>> GPR16: 00945b20 009402f8 00000001 a6b87550 a51fd000 afb73220 a6b22c78 >>>>> a6a6aecc >>>>> GPR24: 00000000 ffffffc0 00000020 00000008 a5205eb0 00000000 e2f75f40 >>>>> 000000ae >>>>> NIP [c0011474] system_call_exception+0x60/0x164 >>>>> LR [c0011464] system_call_exception+0x50/0x164 >>>>> Call Trace: >>>>> [e2f75f00] [00009000] 0x9000 (unreliable) >>>>> [e2f75f30] [c001604c] ret_from_syscall+0x0/0x28 >>>>> --- interrupt: c00 at 0xa69d6cb0 >>>>> NIP: a69d6cb0 LR: a69d6c3c CTR: 00000000 >>>>> REGS: e2f75f40 TRAP: 0c00 Not tainted (5.13.0-pmac-VMAP) >>>>> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 2400446c XER: 20000000 >>>>> >>>>> GPR00: 000000ae a5205de0 a5687ca0 00000000 00000000 a5205eb0 00000008 >>>>> 00000020 >>>>> GPR08: ffffffc0 401201ea 401200d9 ffffffff c158f230 00c1f778 00000000 >>>>> 00000000 >>>>> GPR16: 00945b20 009402f8 00000001 a6b87550 a51fd000 afb73220 a6b22c78 >>>>> a6a6aecc >>>>> GPR24: afb72fc8 00000000 00000001 a5205f30 afb733dc 00000000 a6b85ff4 >>>>> a5205eb0 >>>>> NIP [a69d6cb0] 0xa69d6cb0 >>>>> LR [a69d6c3c] 0xa69d6c3c >>>>> --- interrupt: c00 >>>>> Instruction dump: >>>>> 7cdb3378 93810020 7cbc2b78 93a10024 7c9d2378 93e1002c 7d3f4b78 4800d629 >>>>> 817e0084 931e0088 69690002 5529fffe <0f090000> 69694000 552997fe 0f090000 >>>>> ---[ end trace c66c6c3c44806276 ]--- >>>>> >>> >>> Getting a BUG at arch/powerpc/kernel/interrupt.c:49 meaning MSR_RI is not >>> set, but the c00 interrupt >>> frame shows MSR_RI properly set, so what ? >> >> Could the stack be correct but regs pointer incorrect? >> >> Instruction dump is >> >> 0: 78 33 db 7c mr r27,r6 >> 4: 20 00 81 93 stw r28,32(r1) >> 8: 78 2b bc 7c mr r28,r5 >> c: 24 00 a1 93 stw r29,36(r1) >> 10: 78 23 9d 7c mr r29,r4 >> 14: 2c 00 e1 93 stw r31,44(r1) >> 18: 78 4b 3f 7d mr r31,r9 >> 1c: 29 d6 00 48 bl 0xd644 >> 20: 84 00 7e 81 lwz r11,132(r30) >> 24: 88 00 1e 93 stw r24,136(r30) >> 28: 02 00 69 69 xori r9,r11,2 >> 2c: fe ff 29 55 rlwinm r9,r9,31,31,31 >> 30: 00 00 09 0f twnei r9,0 >> 34: 00 40 69 69 xori r9,r11,16384 >> 38: fe 97 29 55 rlwinm r9,r9,18,31,31 >> 3c: 00 00 09 0f twnei r9,0 >> >> regs->msr is in r11 == 0xce030005 so some kernel address? >> >> r1 == 0xe2f75f00 >> r30 == 0xe2f75f40 >> >> I think that matches if the function allocates 48 bytes of stack. >> STACK_FRAME_OVERHEAD is 16, so the difference would be 0x40 in that >> case. Seems okay. >> >> I'm not sure then. Can you get a hash fault interrupt come in here >> because of the vmap stack access and clobber r11? Hmm... >> >> fast_hash_page_return: >> andis. r10, r9, SRR1_ISI_NOPT@h /* Set on ISI, cleared on >> DSI */ >> >> Is that really right? DSI can set this bit for NOHPTE as well no? > > On DSI, the error bits are in DSISR while they are in SRR1 on ISI. > > r9 is supposed to contain SRR1 in both cases. Powerpc 32 bits programming > manual explicitely says > that bits 1-4 and 10-15 of SRR1 are cleared on DSI.
Ah right, I had in mind it was DSISR on DSI and SRR1 on ISI because we put them together early on 64s. Can't think of anything else at the moment. Thanks, Nick
