GCC 4.5 introduces behavior that forces the alignment of structures to
use the largest possible value. The default value is 32 bytes, so if
some structures are defined with a 4-byte alignment and others aren't
declared with an alignment constraint at all - it will align at 32-bytes.
For things like the ftrace events, this results in a non-standard array.
When initializing the ftrace subsystem, we traverse the _ftrace_events
section and call the initialization callback for each event. When the
structures are misaligned, we could be treating another part of the
structure (or the zeroed out space between them) as a function pointer.
This patch forces the alignment for all the ftrace_event_call structures
to 4 bytes.
Without this patch, the kernel fails to boot very early when built with
gcc 4.5.
It's trivial to check the alignment of the members of the array, so it
might be worthwhile to add something to the build system to do that
automatically. Unfortunately, that only covers this case. I've asked one
of the gcc developers about adding a warning when this condition is seen.
Cc: stable@kernel.org
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
LKML-Reference: <4B85770B.6010901@suse.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code in stop_machine that modifies the kernel text has a bit
of logic to handle the case of NMIs. stop_machine does not prevent
NMIs from executing, and if an NMI were to trigger on another CPU
as the modifying CPU is changing the NMI text, a GPF could result.
To prevent the GPF, the NMI calls ftrace_nmi_enter() which may
modify the code first, then any other NMIs will just change the
text to the same content which will do no harm. The code that
stop_machine called must wait for NMIs to finish while it changes
each location in the kernel. That code may also change the text
to what the NMI changed it to. The key is that the text will never
change content while another CPU is executing it.
To make the above work, the call to ftrace_nmi_enter() must also
do a smp_mb() as well as atomic_inc(). But for applications like
perf that require a high number of NMIs for profiling, this can have
a dramatic effect on the system. Not only is it doing a full memory
barrier on both nmi_enter() as well as nmi_exit() it is also
modifying a global variable with an atomic operation. This kills
performance on large SMP machines.
Since the memory barriers are only needed when ftrace is in the
process of modifying the text (which is seldom), this patch
adds a "modifying_code" variable that gets set before stop machine
is executed and cleared afterwards.
The NMIs will check this variable and store it in a per CPU
"save_modifying_code" variable that it will use to check if it
needs to do the memory barriers and atomic dec on NMI exit.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Set the PCI CLS early in the boot process to prevent
device failures. In pcibios_set_master use the new
pci_cache_line_size instead of a hard-coded value.
Signed-off-by: Carlos O'Donell <carlos@codesourcery.com>
Reviewed-by: Grant Grundler <grundler@google.com>
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Trailing semicolon causes compilation involving out_le32() to fail.
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
I create wrong asm code but none test shows that this part of code is wrong.
I am not convinces that were good idea to create asm optimized macros
for caches. The reason is that there is not optimization with previous code
that's why make sense to add old code and do some benchmarking which
functions are faster.
Signed-off-by: Michal Simek <monstr@monstr.eu>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
net: bug fix for vlan + gro issue
tc35815: Remove a wrong netif_wake_queue() call which triggers BUG_ON
cdc_ether: new PID for Ericsson C3607w to the whitelist (resubmit)
IPv6: better document max_addresses parameter
MAINTAINERS: update mv643xx_eth maintenance status
e1000: Fix DMA mapping error handling on RX
iwlwifi: sanity check before counting number of tfds can be free
iwlwifi: error checking for number of tfds in queue
iwlwifi: set HT flags after channel in rxon
Traffic (tcp) doesnot start on a vlan interface when gro is enabled.
Even the tcp handshake was not taking place.
This is because, the eth_type_trans call before the netif_receive_skb
in napi_gro_finish() resets the skb->dev to napi->dev from the previously
set vlan netdev interface. This causes the ip_route_input to drop the
incoming packet considering it as a packet coming from a martian source.
I could repro this on 2.6.32.7 (stable) and 2.6.33-rc7.
With this fix, the traffic starts and the test runs fine on both vlan
and non-vlan interfaces.
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: Be in TS_POLLING state during mwait based C-state entry
ACPI: Fix regression where _PPC is not read at boot even when ignore_ppc=0
acer-wmi: Respect current backlight level when loading
* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/vmwgfx: Fix queries if no dma buffer thrashing is occuring.
drm/nv50: fix vram ptes on IGPs to point at stolen system memory
drm/nv50: fix instmem binding on IGPs to point at stolen system memory
drm/nv50: improve vram page table construction
drm/nv50: more efficient clearing of gpu page table entries
drm/nv50: make nv50_mem_vm_{bind,unbind} operate only on vram
drm/nouveau: Fix up pre-nv17 analog load detection.
Revert the change made to arch/ia64/sn/kernel/setup.c by commit
204fba4aa3 as it breaks the build.
Fixing the build the b94b08081f way
breaks xpc because genksyms then fails to generate an CRC for
per_cpu____sn_cnodeid_to_nasid because of limitations in the
generic genksyms code.
Signed-off-by: Hedi Berriche <hedi@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The netif_wake_queue() is called correctly (i.e. only on !txfull
condition) from txdone routine. So Unconditional call to the
netif_wake_queue() here is wrong. This might cause calling of
start_xmit routine on txfull state and trigger BUG_ON.
This bug does not happen when NAPI disabled. After txdone there
must be at least one free tx slot. But with NAPI, this is not
true anymore and the BUG_ON can hits on heavy load.
In this driver NAPI was enabled on 2.6.33-rc1 so this is
regression from 2.6.32 kernel.
Reported-by: Ralf Roesch <ralf.roesch@rw-gmbh.de>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ingo Molnar
Wenji Huang
Li Zefan
Jeff Mahoney
Steven Rostedt
Linus Torvalds
Carlos O'Donell
Steven J. Magnani
Michal Simek
Ajit Khaparde
Hedi Berriche
David S. Miller
Atsushi Nemoto
Torgny Johansson