diff options
| author | Andrew Bresticker <abrestic@rivosinc.com> | 2022-11-11 17:31:08 -0500 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2022-12-08 15:31:41 -0800 |
| commit | b0f4c74eadbf69a3298f38566bfaa2e202541f2f (patch) | |
| tree | 3649e1b646debcce73812fe98394e437763ed2af /arch/riscv/kernel/signal.c | |
| parent | 9abf2313adc1ca1b6180c508c25f22f9395cc780 (diff) | |
RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path
The return to userspace path in entry.S may enable interrupts without the
corresponding lockdep annotation, producing a splat[0] when DEBUG_LOCKDEP
is enabled. Simply calling __trace_hardirqs_on() here gets a bit messy
due to the use of RA to point back to ret_from_exception, so just move
the whole slow-path loop into C. It's more readable and it lets us use
local_irq_{enable,disable}(), avoiding the need for manual annotations
altogether.
[0]:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())
WARNING: CPU: 2 PID: 1 at kernel/locking/lockdep.c:5512 check_flags+0x10a/0x1e0
Modules linked in:
CPU: 2 PID: 1 Comm: init Not tainted 6.1.0-rc4-00160-gb56b6e2b4f31 #53
Hardware name: riscv-virtio,qemu (DT)
epc : check_flags+0x10a/0x1e0
ra : check_flags+0x10a/0x1e0
<snip>
status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[<ffffffff808edb90>] lock_is_held_type+0x78/0x14e
[<ffffffff8003dae2>] __might_resched+0x26/0x22c
[<ffffffff8003dd24>] __might_sleep+0x3c/0x66
[<ffffffff80022c60>] get_signal+0x9e/0xa70
[<ffffffff800054a2>] do_notify_resume+0x6e/0x422
[<ffffffff80003c68>] ret_from_exception+0x0/0x10
irq event stamp: 44512
hardirqs last enabled at (44511): [<ffffffff808f901c>] _raw_spin_unlock_irqrestore+0x54/0x62
hardirqs last disabled at (44512): [<ffffffff80008200>] __trace_hardirqs_off+0xc/0x14
softirqs last enabled at (44472): [<ffffffff808f9fbe>] __do_softirq+0x3de/0x51e
softirqs last disabled at (44467): [<ffffffff80017760>] irq_exit+0xd6/0x104
---[ end trace 0000000000000000 ]---
possible reason: unannotated irqs-on.
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT")
Link: https://lore.kernel.org/r/20221111223108.1976562-1-abrestic@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/kernel/signal.c')
| -rw-r--r-- | arch/riscv/kernel/signal.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 5c591123c440..bfb2afa4135f 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -313,19 +313,27 @@ static void do_signal(struct pt_regs *regs) } /* - * notification of userspace execution resumption - * - triggered by the _TIF_WORK_MASK flags + * Handle any pending work on the resume-to-userspace path, as indicated by + * _TIF_WORK_MASK. Entered from assembly with IRQs off. */ -asmlinkage __visible void do_notify_resume(struct pt_regs *regs, - unsigned long thread_info_flags) +asmlinkage __visible void do_work_pending(struct pt_regs *regs, + unsigned long thread_info_flags) { - if (thread_info_flags & _TIF_UPROBE) - uprobe_notify_resume(regs); - - /* Handle pending signal delivery */ - if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - do_signal(regs); - - if (thread_info_flags & _TIF_NOTIFY_RESUME) - resume_user_mode_work(regs); + do { + if (thread_info_flags & _TIF_NEED_RESCHED) { + schedule(); + } else { + local_irq_enable(); + if (thread_info_flags & _TIF_UPROBE) + uprobe_notify_resume(regs); + /* Handle pending signal delivery */ + if (thread_info_flags & (_TIF_SIGPENDING | + _TIF_NOTIFY_SIGNAL)) + do_signal(regs); + if (thread_info_flags & _TIF_NOTIFY_RESUME) + resume_user_mode_work(regs); + } + local_irq_disable(); + thread_info_flags = read_thread_flags(); + } while (thread_info_flags & _TIF_WORK_MASK); } |