https://github.com/torvalds/linux
Revision 7efb367320f56fc4d549875b6f3a6940018ef2e5 authored by Mikulas Patocka on 30 August 2016, 20:20:55 UTC, committed by Mike Snitzer on 30 August 2016, 20:20:55 UTC
bio_alloc() can allocate a bio with at most BIO_MAX_PAGES (256) vector entries. However, the incoming bio may have more vector entries if it was allocated by other means. For example, bcache submits bios with more than BIO_MAX_PAGES entries. This results in bio_alloc() failure. To avoid the failure, change the code so that it allocates bio with at most BIO_MAX_PAGES entries. If the incoming bio has more entries, bio_add_page() will fail and a new bio will be allocated - the code that handles bio_add_page() failure already exists in the dm-log-writes target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Josef Bacik <jbacik@fb,com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # v4.1+
1 parent a5d6078
Tip revision: 7efb367320f56fc4d549875b6f3a6940018ef2e5 authored by Mikulas Patocka on 30 August 2016, 20:20:55 UTC
dm log writes: fix bug with too large bios
dm log writes: fix bug with too large bios
Tip revision: 7efb367
Kconfig.debug
config PAGE_EXTENSION
bool "Extend memmap on extra space for more information on page"
---help---
Extend memmap on extra space for more information on page. This
could be used for debugging features that need to insert extra
field for every page. This extension enables us to save memory
by not allocating this extra memory according to boottime
configuration.
config DEBUG_PAGEALLOC
bool "Debug page memory allocations"
depends on DEBUG_KERNEL
depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
depends on !KMEMCHECK
select PAGE_EXTENSION
select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
---help---
Unmap pages from the kernel linear mapping after free_pages().
Depending on runtime enablement, this results in a small or large
slowdown, but helps to find certain types of memory corruption.
For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
fill the pages with poison patterns after free_pages() and verify
the patterns before alloc_pages(). Additionally,
this option cannot be enabled in combination with hibernation as
that would result in incorrect warnings of memory corruption after
a resume because free pages are not saved to the suspend image.
By default this option will have a small overhead, e.g. by not
allowing the kernel mapping to be backed by large pages on some
architectures. Even bigger overhead comes when the debugging is
enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
command line parameter.
config DEBUG_PAGEALLOC_ENABLE_DEFAULT
bool "Enable debug page memory allocations by default?"
default n
depends on DEBUG_PAGEALLOC
---help---
Enable debug page memory allocations by default? This value
can be overridden by debug_pagealloc=off|on.
config PAGE_POISONING
bool "Poison pages after freeing"
select PAGE_EXTENSION
select PAGE_POISONING_NO_SANITY if HIBERNATION
---help---
Fill the pages with poison patterns after free_pages() and verify
the patterns before alloc_pages. The filling of the memory helps
reduce the risk of information leaks from freed data. This does
have a potential performance impact.
Note that "poison" here is not the same thing as the "HWPoison"
for CONFIG_MEMORY_FAILURE. This is software poisoning only.
If unsure, say N
config PAGE_POISONING_NO_SANITY
depends on PAGE_POISONING
bool "Only poison, don't sanity check"
---help---
Skip the sanity checking on alloc, only fill the pages with
poison on free. This reduces some of the overhead of the
poisoning feature.
If you are only interested in sanitization, say Y. Otherwise
say N.
config PAGE_POISONING_ZERO
bool "Use zero for poisoning instead of random data"
depends on PAGE_POISONING
---help---
Instead of using the existing poison value, fill the pages with
zeros. This makes it harder to detect when errors are occurring
due to sanitization but the zeroing at free means that it is
no longer necessary to write zeros when GFP_ZERO is used on
allocation.
Enabling page poisoning with this option will disable hibernation
If unsure, say N
bool
config DEBUG_PAGE_REF
bool "Enable tracepoint to track down page reference manipulation"
depends on DEBUG_KERNEL
depends on TRACEPOINTS
---help---
This is a feature to add tracepoint for tracking down page reference
manipulation. This tracking is useful to diagnose functional failure
due to migration failures caused by page reference mismatches. Be
careful when enabling this feature because it adds about 30 KB to the
kernel code. However the runtime performance overhead is virtually
nil until the tracepoints are actually enabled.
Computing file changes ...