With lockdep support implemented on CRISv32, we get the following splat.
switch_mm() can be called both from the scheduler() (with interrupts
disabled) and from flush_old_exec (via activate_mm()), with interrupts
enabled. Fix it by disabling interrupts in activate_mm(), similar to
powerpc and hexagon.
t======================================================
[ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]
3.19.0-08802-g20bc9f1-dirty #323 Not tainted
------------------------------------------------------
init/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
(mmu_context_lock){+.+...}, at: [<c0009290>] switch_mm+0x22/0xc6
and this task is already holding:
(&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648
which would create a new lock dependency:
(&rq->lock){-.-.-.} -> (mmu_context_lock){+.+...}
but this new dependency connects a HARDIRQ-irq-safe lock:
(&rq->lock){-.-.-.}
... which became HARDIRQ-irq-safe at:
[<c002b03c>] scheduler_tick+0x28/0x5e
[<c0007c6c>] timer_interrupt+0x4e/0x6a
[<c0043ac4>] handle_irq_event_percpu+0x54/0x13c
[<c004343c>] generic_handle_irq+0x2a/0x36
to a HARDIRQ-irq-unsafe lock:
(mmu_context_lock){+.+...}
... which became HARDIRQ-irq-unsafe at:
... [<c0039e60>] __lock_acquire+0x8f8/0x1d9c
[<c0009290>] switch_mm+0x22/0xc6
[<c009c260>] flush_old_exec+0x500/0x5d4
[<c00da4c6>] load_elf_phdrs+0x7a/0x84
[<c00dbdb0>] load_elf_binary+0x21c/0x13b4
[<c009cdb6>] do_execve+0x22/0x2c
[<c001dcf2>] ____call_usermodehelper+0x0/0x154
[<c000581e>] ret_from_kernel_thread+0xe/0x14
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(mmu_context_lock);
local_irq_disable();
lock(&rq->lock);
lock(mmu_context_lock);
<Interrupt>
lock(&rq->lock);
*** DEADLOCK ***
1 lock held by init/1:
#0: (&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648
Call Trace:
[<c019fe9e>] printk+0x0/0x4e
[<c00368f8>] print_shortest_lock_dependencies+0x0/0x15c
[<c0048628>] print_stack_trace+0x0/0x88
[<c0038912>] __lock_is_held+0x3e/0x5e
[<c003b894>] lock_acquire+0x8a/0xcc
[<c01a50c4>] _raw_spin_lock+0x44/0x7a
[<c0009290>] switch_mm+0x22/0xc6
[<c01a06f8>] __schedule+0x0/0x648
[<c01a0d76>] schedule+0x36/0x7c
[<c0037d04>] trace_hardirqs_on+0x0/0x1e
[<c0004e18>] do_work_pending+0x30/0xd4
[<c000591a>] _work_pending+0xe/0x12
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Now that we have stack tracing and irq flags tracing support,
we can also enable lockdep support
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Add stacktrace support, which is required for lockdep and tracing. The
stack tracing simply looks at all kernel text symbols found on the
stack, similar to the trap stack dumping code, which can also be
converted to use this.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Use a call to local_irq_enable() instead of incline asm so that the
irqsoff latency tracer knows that interrupts are enabled here.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Add support irqflags tracing, which is required for things like lockdep
and ftrace.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
CRIS userspace (uClibc for one) expects asm/elf.h to be exported but
this header appears to have gone missing at some point. Move it to
uapi/ and export it.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
We're going to export asm/elf.h; remove its dependencies on the
non-exported asm/user.h and the unused asm/system.h include.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
The exported ptrace.h header on CRIS references an "arch" directory
which does not exist. Fix this by having the variants in the same
directory and including them conditionally, similar to other
architectures.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Fix a number of small issues visible when GPIO is enabled:
- Correct missing default for !ETRAXFS in Kconfig
- Remove information on number of bits for some Kconfigs
related to the GPIO, they are different in ETRAX FS and ARTPEC-3
- Fix compile warning in ARTPEC-3 GPIO driver
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Squash the followng warnings
arch/cris/arch-v32/mach-fs/pinmux.c: In function 'crisv32_pinmux_alloc_fixed':
arch/cris/arch-v32/mach-fs/pinmux.c:104:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
arch/cris/arch-v32/mach-fs/pinmux.c: In function 'crisv32_pinmux_dealloc_fixed':
arch/cris/arch-v32/mach-fs/pinmux.c:238:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
arch/cris/arch-v32/mach-fs/pinmux.c: In function '__crisv32_pinmux_alloc':
arch/cris/arch-v32/mach-fs/pinmux.c:49:1: warning: control reaches end of non-void function [-Wreturn-type]
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Support for verbose BUG reporting already exists, but the HAVE flag that
allows the option to be enabled is missing.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
Add an unreachable() in the BUG() implementations, to get rid of
several warnings similar to the one below:
kernel/sched/core.c: In function 'pick_next_task':
kernel/sched/core.c:2690:1: warning: control reaches end of non-void function [-Wreturn-type]
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
Turn a kmalloc/memset into an equivalent kzalloc.
Doing so also move the zero'ing of the memory outside of a mutex.
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
Rabin Vincent
Jesper Nilsson
Chen Gang
Christophe Jaillet