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| author | Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> | 2017-06-20 19:08:30 -0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-06-23 09:32:11 +0200 |
| commit | 3e401f7a2e5199151f735aee6a5c6b4776e6a35e (patch) | |
| tree | 39a4c4f95362a6a34bede2b3f7c3c4097b43db44 /kernel/cpu.c | |
| parent | 1b3b22507e0d45dedc6a54b26d56e0b8c4d36875 (diff) | |
| download | linux-3e401f7a2e5199151f735aee6a5c6b4776e6a35e.tar.bz2 | |
powerpc: Only obtain cpu_hotplug_lock if called by rtasd
Calling arch_update_cpu_topology from a CPU hotplug state machine callback
hits a deadlock because the function tries to get a read lock on
cpu_hotplug_lock while the state machine still holds a write lock on it.
Since all callers of arch_update_cpu_topology except rtasd already hold
cpu_hotplug_lock, this patch changes the function to use
stop_machine_cpuslocked and creates a separate function for rtasd which
still tries to obtain the lock.
Michael Bringmann investigated the bug and provided a detailed analysis
of the deadlock on this previous RFC for an alternate solution:
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com
Link: https://patchwork.ozlabs.org/patch/771293/
Diffstat (limited to 'kernel/cpu.c')
0 files changed, 0 insertions, 0 deletions