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Date: Sat, 10 Sep 2016 13:27:44 +0200
From: Borislav Petkov <bp@...en8.de>
To: Rui Wang <rui.y.wang@...el.com>
Cc: bhelgaas@...gle.com, torvalds@...ux-foundation.org,
peterz@...radead.org, tglx@...utronix.de, helgaas@...nel.org,
linux-acpi@...r.kernel.org, linux-pci@...r.kernel.org,
rjw@...ysocki.net, tony.luck@...el.com, mingo@...nel.org,
x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: 584c5c422f6c ("x86/ioapic: Support hot-removal of IOAPICs
present during boot")
On Sat, Sep 10, 2016 at 08:14:04AM +0800, Rui Wang wrote:
> Is it a Romley-EP ? What kind of SNB box is it? I'll try to find one
> to reproduce the problem.
You don't have to - I went and analyzed it for you but it is ACPI
crap and I can't be bothered to think of a solution. It looks like
a chicken-and-an-egg issue where you call acpi_ioapic_add() on the
root_bus and something's not initialized there in the chain of parent
and children nodes.
But I could very well be wrong so let me dump the details, I'll let
someone else make sense of it all. Provided I've not made a mistake
somewhere, which is not uncommon.
So the splat is:
[ 4.396872] pci_bus 0000:3f: resource 5 [mem 0x00000000-0x3fffffffffff]
[ 4.403493] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[ 4.411331] IP: [<ffffffff8143ef8d>] acpi_ns_walk_namespace+0x3d/0x18f
[ 4.417878] PGD 0
[ 4.419900] Oops: 0000 [#1] PREEMPT SMP
[ 4.423731] Modules linked in:
[ 4.426791] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc5+ #13
[ 4.433122] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014
[ 4.440506] task: ffff88043be70000 task.stack: ffffc90000020000
[ 4.446405] RIP: 0010:[<ffffffff8143ef8d>] [<ffffffff8143ef8d>] acpi_ns_walk_namespace+0x3d/0x18f
[ 4.455348] RSP: 0000:ffffc90000023d98 EFLAGS: 00010202
[ 4.460641] RAX: ffffffff82dd6ae0 RBX: 0000000000000001 RCX: 0000000000000001
[ 4.467752] RDX: 00000000ffffffff RSI: 0000000000000000 RDI: 0000000000000006
[ 4.474854] RBP: ffffc90000023de8 R08: ffffffff8144bfaa R09: 0000000000000000
[ 4.481962] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 4.489071] R13: ffffffff8144bfaa R14: 0000000000000000 R15: 0000000000000000
[ 4.496187] FS: 0000000000000000(0000) GS:ffff88043de00000(0000) knlGS:0000000000000000
[ 4.504242] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4.509967] CR2: 0000000000000018 CR3: 0000000003e05000 CR4: 00000000000406f0
[ 4.517078] Stack:
[ 4.519079] 0000000000000018 ffffffff82dd6c58 ffffc90000023dc0 00000001ffffffff
[ 4.526476] 0000000000000006 0000000000000000 0000000000001001 ffffffff8144bfaa
[ 4.533876] 0000000000000000 0000000000000000 ffffc90000023e38 ffffffff8143f51d
[ 4.541273] Call Trace:
[ 4.543714] [<ffffffff8144bfaa>] ? setup_res+0x94/0x94
[ 4.548915] [<ffffffff8143f51d>] acpi_walk_namespace+0x9b/0xcf
[ 4.554838] [<ffffffff81fc44c1>] ? ras_debugfs_init+0x1b/0x1b
[ 4.560645] [<ffffffff8144c376>] acpi_ioapic_add+0x33/0x4c
[ 4.566221] [<ffffffff81faf09a>] pci_assign_unassigned_resources+0x4e/0x56
[ 4.573151] [<ffffffff81fc44df>] pcibios_assign_resources+0x1e/0xb4
[ 4.579476] [<ffffffff81fc44c1>] ? ras_debugfs_init+0x1b/0x1b
[ 4.585306] [<ffffffff81000440>] do_one_initcall+0x50/0x190
[ 4.590969] [<ffffffff81f73091>] kernel_init_freeable+0x11e/0x1a6
[ 4.597130] [<ffffffff81854d60>] ? rest_init+0x140/0x140
[ 4.602506] [<ffffffff81854d6e>] kernel_init+0xe/0x110
[ 4.607735] [<ffffffff8185f11a>] ret_from_fork+0x2a/0x40
[ 4.613110] Code: 41 54 41 89 cc 53 bb 01 00 00 00 48 83 ec 28 48 83 fe ff 89 7d d0 4c 0f 44 35 58 7b 99 01 89 55 c8 45 31 ff 41 83 e4 01 89 4d cc <4d> 8b 6e 18 4c 89 45 c0 4c 89 4d b8 c7 45 d4 00 00 00 00 4d 85
[ 4.632554] RIP [<ffffffff8143ef8d>] acpi_ns_walk_namespace+0x3d/0x18f
[ 4.639148] RSP <ffffc90000023d98>
[ 4.642619] CR2: 0000000000000018
[ 4.645944] ---[ end trace 2fbd1c53d9becc2a ]---
[ 4.650562] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[ 4.650562]
[ 4.659694] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
You can see from the call trace how it happens:
pci_assign_unassigned_resources-> acpi_ioapic_add -> ... which you added.
rIP is this:
ffffffff8143ef50 <acpi_ns_walk_namespace>:
ffffffff8143ef50: e8 6b 16 42 00 callq ffffffff818605c0 <__fentry__>
ffffffff8143ef55: 55 push %rbp
ffffffff8143ef56: 48 89 e5 mov %rsp,%rbp
ffffffff8143ef59: 41 57 push %r15
ffffffff8143ef5b: 41 56 push %r14
ffffffff8143ef5d: 49 89 f6 mov %rsi,%r14
ffffffff8143ef60: 41 55 push %r13
ffffffff8143ef62: 41 54 push %r12
ffffffff8143ef64: 41 89 cc mov %ecx,%r12d
ffffffff8143ef67: 53 push %rbx
ffffffff8143ef68: bb 01 00 00 00 mov $0x1,%ebx
ffffffff8143ef6d: 48 83 ec 28 sub $0x28,%rsp
ffffffff8143ef71: 48 83 fe ff cmp $0xffffffffffffffff,%rsi
ffffffff8143ef75: 89 7d d0 mov %edi,-0x30(%rbp)
ffffffff8143ef78: 4c 0f 44 35 58 7b 99 cmove 0x1997b58(%rip),%r14 # ffffffff82dd6ad8 <acpi_gbl_root_node>
ffffffff8143ef7f: 01
ffffffff8143ef80: 89 55 c8 mov %edx,-0x38(%rbp)
ffffffff8143ef83: 45 31 ff xor %r15d,%r15d
ffffffff8143ef86: 41 83 e4 01 and $0x1,%r12d
ffffffff8143ef8a: 89 4d cc mov %ecx,-0x34(%rbp)
ffffffff8143ef8d: 4d 8b 6e 18 mov 0x18(%r14),%r13 <--- faulting insn.
ffffffff8143ef91: 4c 89 45 c0 mov %r8,-0x40(%rbp)
ffffffff8143ef95: 4c 89 4d b8 mov %r9,-0x48(%rbp)
ffffffff8143ef99: c7 45 d4 00 00 00 00 movl $0x0,-0x2c(%rbp)
ffffffff8143efa0: 4d 85 ed test %r13,%r13
In the annotated asm, this is:
.globl acpi_ns_walk_namespace
.type acpi_ns_walk_namespace, @function
acpi_ns_walk_namespace:
.LFB1454:
.loc 1 191 0
.cfi_startproc
.LVL5:
call __fentry__
pushq %rbp #
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp #,
.cfi_def_cfa_register 6
pushq %r15 #
pushq %r14 #
.cfi_offset 15, -24
.cfi_offset 14, -32
movq %rsi, %r14 # start_node, start_node
pushq %r13 #
pushq %r12 #
.cfi_offset 13, -40
.cfi_offset 12, -48
.loc 1 249 0
movl %ecx, %r12d # flags, D.24037
.loc 1 191 0
pushq %rbx #
.cfi_offset 3, -56
.loc 1 213 0
movl $1, %ebx #, level
.LVL6:
.loc 1 191 0
subq $40, %rsp #,
.loc 1 205 0
cmpq $-1, %rsi #, start_node
.loc 1 191 0
movl %edi, -48(%rbp) # type, %sfp
.loc 1 205 0
cmove acpi_gbl_root_node(%rip), %r14 # acpi_gbl_root_node,, start_node
.LVL7:
.loc 1 191 0
movl %edx, -56(%rbp) # max_depth, %sfp
.loc 1 198 0
xorl %r15d, %r15d # node_previously_visited
.LVL8:
.loc 1 249 0
andl $1, %r12d #, D.24037
.loc 1 191 0
movl %ecx, -52(%rbp) # flags, %sfp
.LBB14:
.LBB15:
.loc 1 79 0
movq 24(%r14), %r13 # MEM[(struct acpi_namespace_node *)start_node_1].child, start_node <--- faulting insn
and the relevant piece of C code is:
if (start_node == ACPI_ROOT_OBJECT) {
start_node = acpi_gbl_root_node;
}
/* Null child means "get first node" */
parent_node = start_node;
child_node = acpi_ns_get_next_node(parent_node, NULL);
And parent_node, i.e., start_node is NULL here and
acpi_ns_get_next_node() tries to deref it to get the child:
movq 24(%r14), %r13
HTH.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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