linux-stable.git/kernel/softirq.c, branch linux-2.6.16.y

softirq: remove BUG_ONs which can incorrectly trigger

2006-12-15T00:38:04+00:00

It is possible to have tasklets get scheduled before softirqd has had a chance
to spawn on all CPUs.  This is totally harmless; after success during action
CPU_UP_PREPARE, action CPU_ONLINE will be called, which immediately wakes
softirqd on the appropriate CPU to process the already pending tasklets.  So
there is no danger of having a missed wakeup for any tasklets that were
already pending.

In particular, i386 is affected by this during startup, and is visible when
using a very large initrd; during the time it takes for the initrd to be
decompressed, a timer IRQ can come in and schedule RCU callbacks.  It is also
possible that resending of a hardware IRQ via a softirq triggers the same bug.

Because of different timing conditions, this shows up in all emulators and
virtual machines tested, including Xen, VMware, Virtual PC, and Qemu.  It is
also possible to trigger on native hardware with a large enough initrd,
although I don't have a reliable case demonstrating that.

Signed-off-by: Zachary Amsden 
Signed-off-by: Adrian Bunk

[PATCH] cpu hoptlug: avoid usage of smp_processor_id() in preemptible code

2005-11-07T15:53:29+00:00

Replace smp_processor_id() with any_online_cpu(cpu_online_map) in order to
avoid lots of "BUG: using smp_processor_id() in preemptible [00000001]
code:..." messages in case taking a cpu online fails.

All the traces start at the last notifier_call_chain(...) in kernel/cpu.c.
Since we hold the cpu_control semaphore it shouldn't be any problem to access
cpu_online_map.

The reason why cpu_up failed is simply that the cpu that was supposed to be
taken online wasn't even there.  That is because on s390 we never know when a
new cpu comes and therefore cpu_possible_map consists of only ones and doesn't
reflect reality.

Signed-off-by: Heiko Carstens 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] x86-64: Some cleanup and optimization to the processor data area.

2005-09-12T17:49:58+00:00

- Remove unused irqrsp field
- Remove pda->me
- Optimize set_softirq_pending slightly

Signed-off-by: Andi Kleen 
Signed-off-by: Linus Torvalds

[PATCH] revert bogus softirq changes

2005-07-30T17:49:59+00:00

This snuck in with an x86_64 change.  Thanks to Richard Purdie
 for spotting it.

Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] x86_64: Switch to the interrupt stack when running a softirq in local_bh_enable()

2005-07-29T04:46:02+00:00

This avoids some potential stack overflows with very deep softirq callchains.
i386 does this too.

TOADD CFI annotation

Signed-off-by: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Linux-2.6.12-rc2

2005-04-16T22:20:36+00:00

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!