linux-toradex.git/fs/pstore, branch v3.7.2

pstore: Fix NULL pointer dereference in console writes

2012-11-15T02:30:21+00:00

Passing a NULL id causes a NULL pointer deference in writers such as
erst_writer and efi_pstore_write because they expect to update this id.
Pass a dummy id instead.

This avoids a cascade of oopses caused when the initial
pstore_console_write passes a null which in turn causes writes to the
console causing further oopses in subsequent pstore_console_write calls.

Signed-off-by: Colin Ian King 
Acked-by: Kees Cook 
Cc: stable@vger.kernel.org
Signed-off-by: Anton Vorontsov

pstore: Avoid recursive spinlocks in the oops_in_progress case

2012-09-21T00:04:50+00:00

Like 8250 driver, when pstore is registered as a console,
to avoid recursive spinlocks when panic happening, change the
spin_lock_irqsave to spin_trylock_irqsave when oops_in_progress
is true.

Signed-off-by: liu chuansheng 
Signed-off-by: Anton Vorontsov

pstore/ftrace: Convert to its own enable/disable debugfs knob

2012-09-07T05:16:58+00:00

With this patch we no longer reuse function tracer infrastructure, now
we register our own tracer back-end via a debugfs knob.

It's a bit more code, but that is the only downside. On the bright side we
have:

- Ability to make persistent_ram module removable (when needed, we can
  move ftrace_ops struct into a module). Note that persistent_ram is still
  not removable for other reasons, but with this patch it's just one
  thing less to worry about;

- Pstore part is more isolated from the generic function tracer. We tried
  it already by registering our own tracer in available_tracers, but that
  way we're loosing ability to see the traces while we record them to
  pstore. This solution is somewhere in the middle: we only register
  "internal ftracer" back-end, but not the "front-end";

- When there is only pstore tracing enabled, the kernel will only write
  to the pstore buffer, omitting function tracer buffer (which, of course,
  still can be enabled via 'echo function > current_tracer').

Suggested-by: Steven Rostedt 
Signed-off-by: Anton Vorontsov

pstore/ram: Add missing platform_device_unregister

2012-08-31T22:29:42+00:00

We need to unregister platform device when module exit, this commit fixes
the issue.

Signed-off-by: Jovi Zhang 
Acked-by: Kees Cook 
Signed-off-by: Anton Vorontsov

pstore/ram: Mark ramoops_pstore_write_buf() as notrace

2012-08-04T23:16:47+00:00

write_buf() should be marked as notrace, otherwise it is prone to
recursion.

Though, yet the issue is never triggered in real life, because we run
inside the function tracer, where ftrace does its own recurse protection.

But it's still no good, plus soon we might switch to our own tracer ops,
and then the issue will be fatal. So, let's fix it.

Signed-off-by: Anton Vorontsov

pstore/ram: Fix printk format warning

2012-08-04T23:16:45+00:00

Fix printk format warning (on i386) in pstore:

fs/pstore/ram.c:409:3: warning: format '%lu' expects type 'long unsigned int', but argument 2 has type 'size_t'

Signed-off-by: Randy Dunlap 
Acked-by: Kees Cook 
Signed-off-by: Anton Vorontsov

pstore/ram: Fix possible NULL dereference

2012-08-04T23:16:43+00:00

We can dereference 'cxt->cprz' if console and dump logging are disabled
(which is unlikely, but still possible to do). This patch fixes the issue
by changing the code so that we don't dereference przs at all, we can
just calculate bufsize from console_size and record_size values.

Plus, while at it, the patch improves the buffer size calculation.

After Kay's printk rework, we know the optimal buffer size for console
logging -- it is LOG_LINE_MAX (defined privately in printk.c). Previously,
if only console logging was enabled, we would allocate unnecessary large
buffer in pstore, while we only need LOG_LINE_MAX. (Pstore console logging
is still capable of handling buffers > LOG_LINE_MAX, it will just do
multiple calls to psinfo->write).

Note that I don't export the constant, since we will do even a better
thing soon: we will switch console logging to a new write_buf API, which
will eliminate the need for the additional buffer; and so we won't need
the constant.

Reported-by: Dan Carpenter 
Signed-off-by: Anton Vorontsov 
Acked-by: Kees Cook

pstore/ram: Make tracing log versioned

2012-07-17T23:48:09+00:00

Decoding the binary trace w/ a different kernel might be troublesome
since we convert addresses to symbols. For kernels with minimal changes,
the mappings would probably match, but it's not guaranteed at all.
(But still we could convert the addresses by hand, since we do print
raw addresses.)

If we use modules, the symbols could be loaded at different addresses
from the previously booted kernel, and so this would also fail, but
there's nothing we can do about it.

Also, the binary data format that pstore/ram is using in its ringbuffer
may change between the kernels, so here we too must ensure that we're
running the same kernel.

So, there are two questions really:

1. How to compute the unique kernel tag;
2. Where to store it.

In this patch we're using LINUX_VERSION_CODE, just as hibernation
(suspend-to-disk) does. This way we are protecting from the kernel
version mismatch, making sure that we're running the same kernel
version and patch level. We could use CRC of a symbol table (as
suggested by Tony Luck), but for now let's not be that strict.

And as for storing, we are using a small trick here. Instead of
allocating a dedicated buffer for the tag (i.e. another prz), or
hacking ram_core routines to "reserve" some control data in the
buffer, we are just encoding the tag into the buffer signature
(and XOR'ing it with the actual signature value, so that buffers
not needing a tag can just pass zero, which will result into the
plain old PRZ signature).

Suggested-by: Steven Rostedt 
Suggested-by: Tony Luck 
Suggested-by: Colin Cross 
Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

pstore: Headers should include all stuff they use

2012-07-17T19:15:30+00:00

Headers should really include all the needed prototypes, types, defines
etc. to be self-contained. This is a long-standing issue, but apparently
the new tracing code unearthed it (SMP=n is also a prerequisite):

In file included from fs/pstore/internal.h:4:0,
                 from fs/pstore/ftrace.c:21:
include/linux/pstore.h:43:15: error: field ‘read_mutex’ has incomplete type

While at it, I also added the following:

linux/types.h -> size_t, phys_addr_t, uXX and friends
linux/spinlock.h -> spinlock_t
linux/errno.h -> Exxxx
linux/time.h -> struct timespec (struct passed by value)
struct module and rs_control forward declaration (passed via pointers).

Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Add ftrace messages handling

2012-07-17T17:14:17+00:00

The ftrace log size is configurable via ramoops.ftrace_size
module option, and the log itself is available via
/ftrace-ramoops file.

Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman