Check stack pointer if we are reaching the stack end and stop unwinding
if we do. This fixes early backtraces and avoids showing unrealistic
call stacks.
Signed-off-by: Helge Deller <deller@gmx.de>
While testing UBSAN I saw this BUG:
BUG: spinlock bad magic on CPU#0, swapper/0
in unwind code. Let's avoid that by static initialization.
Signed-off-by: Helge Deller <deller@gmx.de>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes backtrace on PA-RISC
There were several problems:
1) The code that decodes instructions handles instructions that subtract
from the stack pointer incorrectly. If the instruction subtracts the
number X from the stack pointer the code increases the frame size by
(0x100000000-X). This results in invalid accesses to memory and
recursive page faults.
2) Because gcc reorders blocks, handling instructions that subtract from
the frame pointer is incorrect. For example, this function
int f(int a)
{
if (__builtin_expect(a, 1))
return a;
g();
return a;
}
is compiled in such a way, that the code that decreases the stack
pointer for the first "return a" is placed before the code for "g" call.
If we recognize this decrement, we mistakenly believe that the frame
size for the "g" call is zero.
To fix problems 1) and 2), the patch doesn't recognize instructions that
decrease the stack pointer at all. To further safeguard the unwind code
against nonsense values, we don't allow frame size larger than
Total_frame_size.
3) The backtrace is not locked. If stack dump races with module unload,
invalid table can be accessed.
This patch adds a spinlock when processing module tables.
Note, that for correct backtrace, you need recent binutils.
Binutils 2.18 from Debian 5 produce garbage unwind tables.
Binutils 2.21 work better (it sometimes forgets function frames, but at
least it doesn't generate garbage).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Having many dozens of modules, the searches down the linked
list of sections would dominate the lookup time, dwarfing
any savings from the binary search within the section.
A simple move-to-front optimisation exploits the commonality
of the code paths taken, and in simple real-world tests
on other architectures reduced the number of steps in the
search to barely more than 1.
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Kyle McMartin <kyle@redhat.com>
kernel unwinding is broken with gcc >= 4.x. Part of the problem is that
binutils seems very sensitive to where the unwind information is stored.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since unwind_frame_init_from_blocked_task() may be called from
interrupt/in_atomic context, it needs to kmalloc() memory with
GFP_ATOMIC instead of GFP_KERNEL.
This fixes this warning (ShowTasks called from sysrq handler):
BUG: sleeping function called from invalid context at mm/slab.c:3044
in_atomic(): 1, irqs_disabled(): 1, pid: 2119, name: miniruby
Backtrace:
[<10132e78>] __might_sleep+0x4c/0x118
[<1018f644>] kmem_cache_alloc+0x2c/0xb4
[<1011bae0>] unwind_frame_init_from_blocked_task+0x30/0xa0
[<1010fd3c>] parisc_show_stack+0x3c/0xac
[<10132c7c>] show_state_filter+0x80/0xd8
[<102f4074>] __handle_sysrq+0xd0/0x1b0
[<102f9558>] receive_chars+0x22c/0x318
[<102f9940>] serial8250_handle_port+0x40/0x88
[<102f9a8c>] serial8250_interrupt+0x104/0x10c
[<10161920>] handle_IRQ_event+0x44/0x94
[<10161acc>] __do_IRQ+0x15c/0x1dc
[<102c442c>] superio_interrupt+0x74/0xa8
[<10161920>] handle_IRQ_event+0x44/0x94
[<10161acc>] __do_IRQ+0x15c/0x1dc
[<10110fb4>] do_cpu_irq_mask+0x90/0xbc
[<10114068>] intr_return+0x0/0x4
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
The unwinder was being initialized way too late to be any use
debugging early boot crashes. Instead of relying on module_init
initcalls to initialize it, let's do it explicitly as early as
we can.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
KSYM_NAME_LEN is peculiar in that it does not include the space for the
trailing '\0', forcing all users to use KSYM_NAME_LEN + 1 when allocating
buffer. This is nonsense and error-prone. Moreover, when the caller
forgets that it's very likely to subtly bite back by corrupting the stack
because the last position of the buffer is always cleared to zero.
This patch increments KSYM_NAME_LEN by one and updates code accordingly.
* off-by-one bug in asm-powerpc/kprobes.h::kprobe_lookup_name() macro
is fixed.
* Where MODULE_NAME_LEN and KSYM_NAME_LEN were used together,
MODULE_NAME_LEN was treated as if it didn't include space for the
trailing '\0'. Fix it.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add special-case handling for "handle_interruption" so that we can rewind
past the interruption. This is useful for seeing what caused a BUG() or
WARN_ON(); otherwise the unwind stops at the interruption.
Signed-off-by: Randolph Chung <tausq@debian.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
The unwinder was broken by the shift of PAGE_OFFSET in order to increase the
size of the vmalloc area on 64-bit kernels.
Signed-off-by: Randolph Chung <tausq@debian.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
commit ffb4512276 removed one too many args.
kallsyms_lookup is not safe to call with a NULL *modname. Paper bag over the
problem for the time being.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Several kallsyms_lookup() pass dummy arguments but only need, say, module's
name. Make kallsyms_lookup() accept NULLs where possible.
Also, makes picture clearer about what interfaces are needed for all symbol
resolving business.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Al Viro did this for x86-64 and reduced the number of dependencies on
sched.h significantly. We had a couple of files which were relying on
uaccess.h pulling in sched.h, so they need explicit dependencies added.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Run this:
#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done
And then go through and reinstate those cases where code is casting pointers
to non-pointers.
And then drop a few hunks which conflicted with outstanding work.
Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Flag a whole bunch of things as __read_mostly on parisc. Also flag a few
branches as unlikely() and cleanup a bit of code.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
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!
