• Catalin Marinas's avatar
    arm64: Add trace_hardirqs_off annotation in ret_to_user · d2e646c7
    Catalin Marinas authored
    commit db3899a6 upstream.
    
    When a kernel is built with CONFIG_TRACE_IRQFLAGS the following warning
    is produced when entering userspace for the first time:
    
      WARNING: at /work/Linux/linux-2.6-aarch64/kernel/locking/lockdep.c:3519
      Modules linked in:
      CPU: 1 PID: 1 Comm: systemd Not tainted 4.4.0-rc3+ #639
      Hardware name: Juno (DT)
      task: ffffffc9768a0000 ti: ffffffc9768a8000 task.ti: ffffffc9768a8000
      PC is at check_flags.part.22+0x19c/0x1a8
      LR is at check_flags.part.22+0x19c/0x1a8
      pc : [<ffffffc0000fba6c>] lr : [<ffffffc0000fba6c>] pstate: 600001c5
      sp : ffffffc9768abe10
      x29: ffffffc9768abe10 x28: ffffffc9768a8000
      x27: 0000000000000000 x26: 0000000000000001
      x25: 00000000000000a6 x24: ffffffc00064be6c
      x23: ffffffc0009f249e x22: ffffffc9768a0000
      x21: ffffffc97fea5480 x20: 00000000000001c0
      x19: ffffffc00169a000 x18: 0000005558cc7b58
      x17: 0000007fb78e3180 x16: 0000005558d2e238
      x15: ffffffffffffffff x14: 0ffffffffffffffd
      x13: 0000000000000008 x12: 0101010101010101
      x11: 7f7f7f7f7f7f7f7f x10: fefefefefefeff63
      x9 : 7f7f7f7f7f7f7f7f x8 : 6e655f7371726964
      x7 : 0000000000000001 x6 : ffffffc0001079c4
      x5 : 0000000000000000 x4 : 0000000000000001
      x3 : ffffffc001698438 x2 : 0000000000000000
      x1 : ffffffc9768a0000 x0 : 000000000000002e
      Call trace:
      [<ffffffc0000fba6c>] check_flags.part.22+0x19c/0x1a8
      [<ffffffc0000fc440>] lock_is_held+0x80/0x98
      [<ffffffc00064bafc>] __schedule+0x404/0x730
      [<ffffffc00064be6c>] schedule+0x44/0xb8
      [<ffffffc000085bb0>] ret_to_user+0x0/0x24
      possible reason: unannotated irqs-off.
      irq event stamp: 502169
      hardirqs last  enabled at (502169): [<ffffffc000085a98>] el0_irq_naked+0x1c/0x24
      hardirqs last disabled at (502167): [<ffffffc0000bb3bc>] __do_softirq+0x17c/0x298
      softirqs last  enabled at (502168): [<ffffffc0000bb43c>] __do_softirq+0x1fc/0x298
      softirqs last disabled at (502143): [<ffffffc0000bb830>] irq_exit+0xa0/0xf0
    
    This happens because we disable interrupts in ret_to_user before calling
    schedule() in work_resched. This patch adds the necessary
    trace_hardirqs_off annotation.
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Reported-by: default avatarMark Rutland <mark.rutland@arm.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    Cc: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    
    d2e646c7
entry.S 17.1 KB