• Yang Shi's avatar
    arm64: replace read_lock to rcu lock in call_break_hook · 62c6c61a
    Yang Shi authored
    BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
    in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
    1 lock held by perf/342:
     #0:  (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
    irq event stamp: 62224
    hardirqs last  enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
    hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
    softirqs last  enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
    softirqs last disabled at (0): [<          (null)>]           (null)
    CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
    Hardware name: linux,dummy-virt (DT)
    Call trace:
    [<ffffffc000089968>] dump_backtrace+0x0/0x128
    [<ffffffc000089ab0>] show_stack+0x20/0x30
    [<ffffffc0007030d0>] dump_stack+0x7c/0xa0
    [<ffffffc0000c878c>] ___might_sleep+0x174/0x260
    [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
    [<ffffffc000708db0>] rt_read_lock+0x60/0x80
    [<ffffffc0000851a8>] call_break_hook+0x30/0xd0
    [<ffffffc000085a70>] brk_handler+0x30/0x98
    [<ffffffc000082248>] do_debug_exception+0x50/0xb8
    Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
    fe20:                                     00000000 00000000 c1594680 0000007f
    fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
    fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
    fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
    fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
    fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
    fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
    ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
    ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
    ff40: 928e4cc0 0000007f 91ff11e8 0000007f
    
    call_break_hook is called in atomic context (hard irq disabled), so replace
    the sleepable lock to rcu lock, replace relevant list operations to rcu
    version and call synchronize_rcu() in unregister_break_hook().
    
    And, replace write lock to spinlock in {un}register_break_hook.
    Signed-off-by: default avatarYang Shi <yang.shi@linaro.org>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    62c6c61a
debug-monitors.c 9.8 KB