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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-08-04 18:24:10 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-08-18 08:59:17 +0200 |
| commit | fc7da433fa16b7e9a9efa92b41f684670535d99e (patch) | |
| tree | 06219577bd99675feb62904eda10d7f6843a188c | |
| parent | 312730cd15e097c11c4d0a0b8583a89a9ffd3d96 (diff) | |
| download | linux-stable-fc7da433fa16b7e9a9efa92b41f684670535d99e.tar.gz linux-stable-fc7da433fa16b7e9a9efa92b41f684670535d99e.tar.bz2 linux-stable-fc7da433fa16b7e9a9efa92b41f684670535d99e.zip | |
powerpc/smp: Fix OOPS in topology_init()
commit 8241461536f21bbe51308a6916d1c9fb2e6b75a7 upstream.
Running an SMP kernel on an UP platform not prepared for it,
I encountered the following OOPS:
BUG: Kernel NULL pointer dereference on read at 0x00000034
Faulting instruction address: 0xc0a04110
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K SMP NR_CPUS=2 CMPCPRO
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-pmac-00001-g230fedfaad21 #5234
NIP: c0a04110 LR: c0a040d8 CTR: c0a04084
REGS: e100dda0 TRAP: 0300 Not tainted (5.13.0-pmac-00001-g230fedfaad21)
MSR: 00009032 <EE,ME,IR,DR,RI> CR: 84000284 XER: 00000000
DAR: 00000034 DSISR: 20000000
GPR00: c0006bd4 e100de60 c1033320 00000000 00000000 c0942274 00000000 00000000
GPR08: 00000000 00000000 00000001 00000063 00000007 00000000 c0006f30 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000005
GPR24: c0c67d74 c0c67f1c c0c60000 c0c67d70 c0c0c558 1efdf000 c0c00020 00000000
NIP [c0a04110] topology_init+0x8c/0x138
LR [c0a040d8] topology_init+0x54/0x138
Call Trace:
[e100de60] [80808080] 0x80808080 (unreliable)
[e100de90] [c0006bd4] do_one_initcall+0x48/0x1bc
[e100def0] [c0a0150c] kernel_init_freeable+0x1c8/0x278
[e100df20] [c0006f44] kernel_init+0x14/0x10c
[e100df30] [c00190fc] ret_from_kernel_thread+0x14/0x1c
Instruction dump:
7c692e70 7d290194 7c035040 7c7f1b78 5529103a 546706fe 5468103a 39400001
7c641b78 40800054 80c690b4 7fb9402e <81060034> 7fbeea14 2c080000 7fa3eb78
---[ end trace b246ffbc6bbbb6fb ]---
Fix it by checking smp_ops before using it, as already done in
several other places in the arch/powerpc/kernel/smp.c
Fixes: 39f87561454d ("powerpc/smp: Move ppc_md.cpu_die() to smp_ops.cpu_offline_self()")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/75287841cbb8740edd44880fe60be66d489160d9.1628097995.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/powerpc/kernel/sysfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 2e08640bb3b4..d36e71ba002c 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -1167,7 +1167,7 @@ static int __init topology_init(void) * CPU. For instance, the boot cpu might never be valid * for hotplugging. */ - if (smp_ops->cpu_offline_self) + if (smp_ops && smp_ops->cpu_offline_self) c->hotpluggable = 1; #endif |