https://github.com/torvalds/linux
Revision 8a46f71d343814a07f37d209e6b15b2a6573f8da authored by Matt Redfearn on 01 November 2017, 16:45:56 UTC, committed by James Hogan on 01 November 2017, 21:05:57 UTC
Commit 1ec9dd80bedc ("MIPS: CPS: Detect CPUs in secondary clusters") added a check in cps_boot_secondary() that the secondary being booted is in the same cluster as the CPU running this code. This check is performed using current_cpu_data without disabling preemption. As such when CONFIG_PREEMPT=y, a BUG is triggered: [ 57.991693] BUG: using smp_processor_id() in preemptible [00000000] code: hotplug/1749 <snip> [ 58.063077] Call Trace: [ 58.065842] [<8040cdb4>] show_stack+0x84/0x114 [ 58.070830] [<80b11b38>] dump_stack+0xf8/0x140 [ 58.075796] [<8079b12c>] check_preemption_disabled+0xec/0x118 [ 58.082204] [<80415110>] cps_boot_secondary+0x84/0x44c [ 58.087935] [<80413a14>] __cpu_up+0x34/0x98 [ 58.092624] [<80434240>] bringup_cpu+0x38/0x114 [ 58.097680] [<80434af0>] cpuhp_invoke_callback+0x168/0x8f0 [ 58.103801] [<804362d0>] _cpu_up+0x154/0x1c8 [ 58.108565] [<804363dc>] do_cpu_up+0x98/0xa8 [ 58.113333] [<808261f8>] device_online+0x84/0xc0 [ 58.118481] [<80826294>] online_store+0x60/0x98 [ 58.123562] [<8062261c>] kernfs_fop_write+0x158/0x1d4 [ 58.129196] [<805a2ae4>] __vfs_write+0x4c/0x168 [ 58.134247] [<805a2dc8>] vfs_write+0xe0/0x190 [ 58.139095] [<805a2fe0>] SyS_write+0x68/0xc4 [ 58.143854] [<80415d58>] syscall_common+0x34/0x58 In reality we don't currently support running the kernel on CPUs not in cluster 0, so the answer to cpu_cluster(¤t_cpu_data) will always be 0, even if this task being preempted and continues running on a different CPU. Regardless, the BUG should not be triggered, so fix this by switching to raw_current_cpu_data. When multicluster support lands upstream this check will need removing or changing anyway. Fixes: 1ec9dd80bedc ("MIPS: CPS: Detect CPUs in secondary clusters") Signed-off-by: Matt Redfearn <matt.redfearn@mips.com> Reviewed-by: Paul Burton <paul.burton@mips.com> CC: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17563/ Signed-off-by: James Hogan <jhogan@kernel.org>
1 parent 9e8c399
Tip revision: 8a46f71d343814a07f37d209e6b15b2a6573f8da authored by Matt Redfearn on 01 November 2017, 16:45:56 UTC
MIPS: CPS: Fix use of current_cpu_data in preemptible code
MIPS: CPS: Fix use of current_cpu_data in preemptible code
Tip revision: 8a46f71
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arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.3 KB |
.mailmap | -rw-r--r-- | 8.4 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 96.1 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 420.4 KB |
Makefile | -rw-r--r-- | 58.4 KB |
README | -rw-r--r-- | 722 bytes |
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