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linux_dsm_epyc7002/kernel/locking
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Bart Van Assche 90c1cba2b3 locking/lockdep: Zap lock classes even with lock debugging disabled 
The following commit:

  a0b0fd53e1 ("locking/lockdep: Free lock classes that are no longer in use")

changed the behavior of lockdep_free_key_range() from
unconditionally zapping lock classes into only zapping lock classes if
debug_lock == true. Not zapping lock classes if debug_lock == false leaves
dangling pointers in several lockdep datastructures, e.g. lock_class::name
in the all_lock_classes list.

The shell command "cat /proc/lockdep" causes the kernel to iterate the
all_lock_classes list. Hence the "unable to handle kernel paging request" cash
that Shenghui encountered by running cat /proc/lockdep.

Since the new behavior can cause cat /proc/lockdep to crash, restore the
pre-v5.1 behavior.

This patch avoids that cat /proc/lockdep triggers the following crash
with debug_lock == false:

  BUG: unable to handle kernel paging request at fffffbfff40ca448
  RIP: 0010:__asan_load1+0x28/0x50
  Call Trace:
   string+0xac/0x180
   vsnprintf+0x23e/0x820
   seq_vprintf+0x82/0xc0
   seq_printf+0x92/0xb0
   print_name+0x34/0xb0
   l_show+0x184/0x200
   seq_read+0x59e/0x6c0
   proc_reg_read+0x11f/0x170
   __vfs_read+0x4d/0x90
   vfs_read+0xc5/0x1f0
   ksys_read+0xab/0x130
   __x64_sys_read+0x43/0x50
   do_syscall_64+0x71/0x210
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Reported-by: shenghui <shhuiw@foxmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: a0b0fd53e1 ("locking/lockdep: Free lock classes that are no longer in use") # v5.1-rc1.
Link: https://lkml.kernel.org/r/20190403233552.124673-1-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-10 13:45:59 +02:00
..
lockdep_internals.h locking/lockdep: Introduce lockdep_next_lockchain() and lock_chain_count() 2019-02-28 07:55:44 +01:00
lockdep_proc.c locking/lockdep: Introduce lockdep_next_lockchain() and lock_chain_count() 2019-02-28 07:55:44 +01:00
lockdep_states.h
lockdep.c locking/lockdep: Zap lock classes even with lock debugging disabled 2019-04-10 13:45:59 +02:00
locktorture.c Merge branches 'doc.2019.01.26a', 'fixes.2019.01.26a', 'sil.2019.01.26a', 'spdx.2019.02.09a', 'srcu.2019.01.26a' and 'torture.2019.01.26a' into HEAD 2019-02-09 08:47:52 -08:00
Makefile
mcs_spinlock.h
mutex-debug.c locking/mutex: Replace spin_is_locked() with lockdep 2018-11-12 09:06:22 -08:00
mutex-debug.h
mutex.c kernel/locking/mutex.c: remove caller signal_pending branch predictions 2019-01-04 13:13:48 -08:00
mutex.h
osq_lock.c
percpu-rwsem.c
qrwlock.c
qspinlock_paravirt.h mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
qspinlock_stat.h locking/qspinlock_stat: Track the no MCS node available case 2019-02-04 09:03:30 +01:00
qspinlock.c locking/qspinlock: Remove unnecessary BUG_ON() call 2019-02-28 07:55:38 +01:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex.c futex: Handle early deadlock return correctly 2019-02-08 13:00:36 +01:00
rtmutex.h
rwsem-spinlock.c
rwsem-xadd.c sched/wake_q: Reduce reference counting for special users 2019-02-04 09:03:28 +01:00
rwsem.c locking/rwsem: Make owner store task pointer of last owning reader 2018-09-10 12:04:07 +02:00
rwsem.h locking/rwsem: Make owner store task pointer of last owning reader 2018-09-10 12:04:07 +02:00
semaphore.c
spinlock_debug.c
spinlock.c
test-ww_mutex.c locking/ww_mutex: Fix runtime warning in the WW mutex selftest 2018-10-03 08:56:31 +02:00