History log of /haiku/src/system/libroot/posix/malloc_debug/guarded_heap.cpp
Revision Date Author Comments
# 8b9bb054 23-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Replace two more uses of printf in guarded heap.

Use the internal print_stdout() instead as done when printing the
stack traces.


# 5dbea469 23-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Track freeing thread in guarded heap separatley.

Previously the thread member was overwritten with the freeing thread
when a page was freed, leading to confusion when hitting unallocated
pages due to the debugger message still stating "allocated by thread".

Track the freeing thread separately as it might be interesting to know
both, which thread initially allocated and which thread eventually freed
an allocation.


# c4a9344a 20-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Support alignments > B_PAGE_SIZE in guarded heap.

These are always allocated using an area. The allocation size is
increased as to guarantee the availability of a suitable address. The
pages between the allocation info and the actual, aligned start address
and the pages past the allocation end are then protected.

This commit also fixes corruption of the allocation info for large
allocations that used areas. The alignment wasn't taken into account
when calculating the amount of space needed. The alignment could then
lead to rounding down the allocation start such that it would overlap
with the allocation info.


# 1748116d 13-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug.so: Fix missing alignment in guarded realloc.


# 8fa441bf 13-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Revert to a legacy default alignment of 8.

This reverts the legacy default alignment (in absence of max_align_t)
to 8, as it was before.


# f474606e 12-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Merge guarded heap into libroot_debug.

The individual debug heap implementations are now exposed via a
structure of function pointers and a common frontend dispatches the
malloc and malloc_debug APIs through them.

The MALLOC_DEBUG environment variable can be used to select the guarded
heap by adding 'g', otherwise the debug heap is used as the default.
Consequently the separate libroot_guarded is not needed anymore and has
been removed.

To allow the use of environment variables this early, init_env_post_heap
has been added and the heap dependent atfork() moved there. This allowed
to fold the code of init_heap_post_env into init_heap so the former has
been removed.


# 3dfbe1a1 11-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

guarded_heap: Use __arch_get_stack_trace() instead of syscall.

The stack base and end addresses are stored in TLS slots that are
prepared when enabling stack traces and filled in lazily on use for
each thread. This avoids the need of calling get_thread_info to get
these values.

Also simplifies the code somewhat due to proper frame skipping support.


# bd5dea31 11-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

guarded_heap: Replace symbol lookup syscall with runtime_loader.

Use the private runtime_loader API to do the symbol lookup instead of
using the syscall.


# 74c28454 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Remove condition that is always true.


# ec0190ad 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Implement allocation dump on exit in guarded heap.

When enabled (using heap_debug_dump_allocations_on_exit(true) or
MALLOC_DEBUG=e) this causes a dump of all remaining allocations when
libroot_debug is unloaded. It uses terminate_after to be called as
late as possible.

When combined with alloc stack traces this makes for a nice if a bit
crude leak checker. Note that a lot of allocations usually remain
even at that stage due to statically, lazyly and globally allocated
stuff from the various system libraries where it isn't necessarily
worth the overhead to free them when the program terminates anyway.


# e26a4e7b 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Also print stack traces when dumping guarded heap.


# 607ac916 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Impl. heap_debug_dump_allocations in guarded heap.


# 158e20e6 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Implement alloc/free stack traces in guarded heap.

When configured to do so (using heap_debug_set_stack_trace_depth(depth)
or MALLOC_DEBUG=s<depth>) the guarded heap now captures stack traces on
alloc and free.

A crash due to hitting a guard page or an already freed page now dumps
these stack traces. In the case of use-after-free one can therefore see
both where the allocation was done and where it was freed.

Note that there is a hardcoded maximum stack trace depth of 50 and that
the alloc stack trace takes away space from the free stack trace which
uses up the rest of that maximum.


# abf230a9 07-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Set default alignment to max_align_t if available.

For it to be available we build malloc_debug in C++11 mode when not
using GCC2. Note that max_align_t is not in the std namespace in GCC4
versions prior to GCC 4.9. The extra "using namespace std" is there to
be forward compatible once we update.


# 121655e9 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Add default alignment option.

This allows for something similar as was implemented in 217f090 but
makes it optional and configurable.

The MALLOC_DEBUG environment variable now can take "a<size>" to set
the default alignment to the specified size. Note that not all
alignments may be supported depending on the heap implementation.


# b0e31a9c 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

Revert "malloc_debug: align allocations".

This reverts commit 217f090f9e247d1d4c5644e626642c430fafe4e5.

At least for the guarded heap this completely defeats the purpose. If
software requires a certain alignment it should request it using
memalign explicitly instead of assuming it.


# 37acb83e 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Fix build of guarded_heap after atomic changes.


# 217f090f 04-Mar-2014 Adrien Destugues <pulkomandy@pulkomandy.tk>

malloc_debug: align allocations

* Align all allocations of more than 8 bytes to 8-byte.
* Avoids hitting ASSERTs in WebKit when built in debug mode (it assumes
at least 8 byte alignment)


# 268ddbd7 10-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Fix a few function signatures in the guarded heap.

* Not including malloc.h caused the memalign() signature to not be a C
signature, therefore leading to linking errors. Fix the missing
include and explicitly add extern "C" as well.
* Some remaining asterisk style cleanup.


# 3de38069 10-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Update the guarded heap areas after fork.

We don't actually use them for anything yet though.


# 97680106 06-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Add a userland version of the guarded heap to libroot_debug.

The guarded heap uses mprotect() to protect freed/unallocated pages so
that any access to such a page results in a segfault. It also installs
a segfault handler that in such an event prints some info about the
accessed page and then calls the debugger with a meaningful message.

It implements the same interface as the debug heap so it can simply be
swapped out by changing the Jamfile. As it doesn't support most of the
extra debug features (wall checking is obviously superfluous, but it
also doesn't help in leak checking) and as it is hugely space
inefficient I left it disabled for now.


# 8b9bb054f46a2500dfc4216dca18096da737debc 23-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Replace two more uses of printf in guarded heap.

Use the internal print_stdout() instead as done when printing the
stack traces.


# 5dbea4697074034e7b5887d3ce8e45aebbe32057 23-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Track freeing thread in guarded heap separatley.

Previously the thread member was overwritten with the freeing thread
when a page was freed, leading to confusion when hitting unallocated
pages due to the debugger message still stating "allocated by thread".

Track the freeing thread separately as it might be interesting to know
both, which thread initially allocated and which thread eventually freed
an allocation.


# c4a9344a117d3c918506c5d91300a6ce3554c7a2 20-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Support alignments > B_PAGE_SIZE in guarded heap.

These are always allocated using an area. The allocation size is
increased as to guarantee the availability of a suitable address. The
pages between the allocation info and the actual, aligned start address
and the pages past the allocation end are then protected.

This commit also fixes corruption of the allocation info for large
allocations that used areas. The alignment wasn't taken into account
when calculating the amount of space needed. The alignment could then
lead to rounding down the allocation start such that it would overlap
with the allocation info.


# 1748116d1c5dbfd50da5c8d8e4c53b92b1021029 13-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug.so: Fix missing alignment in guarded realloc.


# 8fa441bf5c9a995d3a66da8eb55d244f4b6c7bbd 13-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Revert to a legacy default alignment of 8.

This reverts the legacy default alignment (in absence of max_align_t)
to 8, as it was before.


# f474606ee92a7afddb5b3b6350a97ffd31e22c42 12-Aug-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Merge guarded heap into libroot_debug.

The individual debug heap implementations are now exposed via a
structure of function pointers and a common frontend dispatches the
malloc and malloc_debug APIs through them.

The MALLOC_DEBUG environment variable can be used to select the guarded
heap by adding 'g', otherwise the debug heap is used as the default.
Consequently the separate libroot_guarded is not needed anymore and has
been removed.

To allow the use of environment variables this early, init_env_post_heap
has been added and the heap dependent atfork() moved there. This allowed
to fold the code of init_heap_post_env into init_heap so the former has
been removed.


# 3dfbe1a12d7da31426474bb7a3c4fc911c53ce02 11-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

guarded_heap: Use __arch_get_stack_trace() instead of syscall.

The stack base and end addresses are stored in TLS slots that are
prepared when enabling stack traces and filled in lazily on use for
each thread. This avoids the need of calling get_thread_info to get
these values.

Also simplifies the code somewhat due to proper frame skipping support.


# bd5dea318a091a3ff074ed1823cd961473177c9a 11-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

guarded_heap: Replace symbol lookup syscall with runtime_loader.

Use the private runtime_loader API to do the symbol lookup instead of
using the syscall.


# 74c284545b37cbe08fd9016ee233422f51e81380 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Remove condition that is always true.


# ec0190adb0a9abe5a796d31468f421896eb47124 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Implement allocation dump on exit in guarded heap.

When enabled (using heap_debug_dump_allocations_on_exit(true) or
MALLOC_DEBUG=e) this causes a dump of all remaining allocations when
libroot_debug is unloaded. It uses terminate_after to be called as
late as possible.

When combined with alloc stack traces this makes for a nice if a bit
crude leak checker. Note that a lot of allocations usually remain
even at that stage due to statically, lazyly and globally allocated
stuff from the various system libraries where it isn't necessarily
worth the overhead to free them when the program terminates anyway.


# e26a4e7b7aae3c824b04ef329c763c293249197f 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Also print stack traces when dumping guarded heap.


# 607ac916ded850874386b8983cc9b09b7d525367 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Impl. heap_debug_dump_allocations in guarded heap.


# 158e20e60e97eaa9845c5d6c90f234855be86fb1 10-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Implement alloc/free stack traces in guarded heap.

When configured to do so (using heap_debug_set_stack_trace_depth(depth)
or MALLOC_DEBUG=s<depth>) the guarded heap now captures stack traces on
alloc and free.

A crash due to hitting a guard page or an already freed page now dumps
these stack traces. In the case of use-after-free one can therefore see
both where the allocation was done and where it was freed.

Note that there is a hardcoded maximum stack trace depth of 50 and that
the alloc stack trace takes away space from the free stack trace which
uses up the rest of that maximum.


# abf230a9ac4750f4cacfb1d4c8610732c15b417c 07-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Set default alignment to max_align_t if available.

For it to be available we build malloc_debug in C++11 mode when not
using GCC2. Note that max_align_t is not in the std namespace in GCC4
versions prior to GCC 4.9. The extra "using namespace std" is there to
be forward compatible once we update.


# 121655e9ee3e7fa6d9244df8c68ad30f9981af8c 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

malloc_debug: Add default alignment option.

This allows for something similar as was implemented in 217f090 but
makes it optional and configurable.

The MALLOC_DEBUG environment variable now can take "a<size>" to set
the default alignment to the specified size. Note that not all
alignments may be supported depending on the heap implementation.


# b0e31a9ce35e3d3d47b59a21e7c43b0d41c11d11 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

Revert "malloc_debug: align allocations".

This reverts commit 217f090f9e247d1d4c5644e626642c430fafe4e5.

At least for the guarded heap this completely defeats the purpose. If
software requires a certain alignment it should request it using
memalign explicitly instead of assuming it.


# 37acb83e4c7f8f946fda8d13f3f64cb721cc3fe3 04-Apr-2015 Michael Lotz <mmlr@mlotz.ch>

libroot_debug: Fix build of guarded_heap after atomic changes.


# 217f090f9e247d1d4c5644e626642c430fafe4e5 04-Mar-2014 Adrien Destugues <pulkomandy@pulkomandy.tk>

malloc_debug: align allocations

* Align all allocations of more than 8 bytes to 8-byte.
* Avoids hitting ASSERTs in WebKit when built in debug mode (it assumes
at least 8 byte alignment)


# 268ddbd76f963f8abca784bfa33f43d779181c72 10-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Fix a few function signatures in the guarded heap.

* Not including malloc.h caused the memalign() signature to not be a C
signature, therefore leading to linking errors. Fix the missing
include and explicitly add extern "C" as well.
* Some remaining asterisk style cleanup.


# 3de380692acab727237c7ca4dbafa2a1ccf3244c 10-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Update the guarded heap areas after fork.

We don't actually use them for anything yet though.


# 97680106f0ecd95f5f8ca7e1aeb33992fba42ccb 06-Dec-2011 Michael Lotz <mmlr@mlotz.ch>

Add a userland version of the guarded heap to libroot_debug.

The guarded heap uses mprotect() to protect freed/unallocated pages so
that any access to such a page results in a segfault. It also installs
a segfault handler that in such an event prints some info about the
accessed page and then calls the debugger with a meaningful message.

It implements the same interface as the debug heap so it can simply be
swapped out by changing the Jamfile. As it doesn't support most of the
extra debug features (wall checking is obviously superfluous, but it
also doesn't help in leak checking) and as it is hugely space
inefficient I left it disabled for now.