linux-toradex.git/mm/util.c, branch v5.13-rc3

mm/util.c: fix typo

2021-05-05T18:27:25+00:00

s/condtion/condition/

Link: https://lkml.kernel.org/r/20210317033439.3429411-1-unixbhaskar@gmail.com
Signed-off-by: Bhaskar Chowdhury 
Acked-by: Randy Dunlap 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/util.c: reduce mem_dump_obj() object size

2021-05-05T18:27:25+00:00

Simplify the code by using a temporary and reduce the object size by
using a single call to pr_cont().  Reverse a test and unindent a block
too.

$ size mm/util.o* (defconfig x86-64)
   text	   data	    bss	    dec	    hex	filename
   7419	    372	     40	   7831	   1e97	mm/util.o.new
   7477	    372	     40	   7889	   1ed1	mm/util.o.old

Link: https://lkml.kernel.org/r/a6e105886338f68afd35f7a13d73bcf06b0cc732.camel@perches.com
Signed-off-by: Joe Perches 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move page_mapping_file to pagemap.h

2021-04-30T18:20:37+00:00

page_mapping_file() is only used by some architectures, and then it
is usually only used in one place.  Make it a static inline function
so other architectures don't have to carry this dead code.

Link: https://lkml.kernel.org/r/20210317123011.350118-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: David Hildenbrand 
Acked-by: Mike Rapoport 
Cc: Huang Ying 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcutorture: Add crude tests for mem_dump_obj()

2021-03-08T22:18:46+00:00

This commit adds a few crude tests for mem_dump_obj() to rcutorture
runs.  Just to prevent bitrot, you understand!

Signed-off-by: Paul E. McKenney

mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels

2021-03-08T22:18:46+00:00

The mem_dump_obj() functionality adds a few hundred bytes, which is a
small price to pay.  Except on kernels built with CONFIG_PRINTK=n, in
which mem_dump_obj() messages will be suppressed.  This commit therefore
makes mem_dump_obj() be a static inline empty function on kernels built
with CONFIG_PRINTK=n and excludes all of its support functions as well.
This avoids kernel bloat on systems that cannot use mem_dump_obj().

Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: 
Suggested-by: Andrew Morton 
Signed-off-by: Paul E. McKenney

mm: Make mem_dump_obj() handle vmalloc() memory

2021-01-22T23:24:04+00:00

This commit adds vmalloc() support to mem_dump_obj().  Note that the
vmalloc_dump_obj() function combines the checking and dumping, in
contrast with the split between kmem_valid_obj() and kmem_dump_obj().
The reason for the difference is that the checking in the vmalloc()
case involves acquiring a global lock, and redundant acquisitions of
global locks should be avoided, even on not-so-fast paths.

Note that this change causes on-stack variables to be reported as
vmalloc() storage from kernel_clone() or similar, depending on the degree
of inlining that your compiler does.  This is likely more helpful than
the earlier "non-paged (local) memory".

Cc: Andrew Morton 
Cc: Joonsoo Kim 
Cc: 
Reported-by: Andrii Nakryiko 
Acked-by: Vlastimil Babka 
Tested-by: Naresh Kamboju 
Signed-off-by: Paul E. McKenney

mm: Make mem_dump_obj() handle NULL and zero-sized pointers

2021-01-22T23:23:57+00:00

This commit makes mem_dump_obj() call out NULL and zero-sized pointers
specially instead of classifying them as non-paged memory.

Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrew Morton 
Cc: 
Reported-by: Andrii Nakryiko 
Acked-by: Vlastimil Babka 
Tested-by: Naresh Kamboju 
Signed-off-by: Paul E. McKenney

mm: Add mem_dump_obj() to print source of memory block

2021-01-22T23:16:01+00:00

There are kernel facilities such as per-CPU reference counts that give
error messages in generic handlers or callbacks, whose messages are
unenlightening.  In the case of per-CPU reference-count underflow, this
is not a problem when creating a new use of this facility because in that
case the bug is almost certainly in the code implementing that new use.
However, trouble arises when deploying across many systems, which might
exercise corner cases that were not seen during development and testing.
Here, it would be really nice to get some kind of hint as to which of
several uses the underflow was caused by.

This commit therefore exposes a mem_dump_obj() function that takes
a pointer to memory (which must still be allocated if it has been
dynamically allocated) and prints available information on where that
memory came from.  This pointer can reference the middle of the block as
well as the beginning of the block, as needed by things like RCU callback
functions and timer handlers that might not know where the beginning of
the memory block is.  These functions and handlers can use mem_dump_obj()
to print out better hints as to where the problem might lie.

The information printed can depend on kernel configuration.  For example,
the allocation return address can be printed only for slab and slub,
and even then only when the necessary debug has been enabled.  For slab,
build with CONFIG_DEBUG_SLAB=y, and either use sizes with ample space
to the next power of two or use the SLAB_STORE_USER when creating the
kmem_cache structure.  For slub, build with CONFIG_SLUB_DEBUG=y and
boot with slub_debug=U, or pass SLAB_STORE_USER to kmem_cache_create()
if more focused use is desired.  Also for slub, use CONFIG_STACKTRACE
to enable printing of the allocation-time stack trace.

Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrew Morton 
Cc: 
Reported-by: Andrii Nakryiko 
[ paulmck: Convert to printing and change names per Joonsoo Kim. ]
[ paulmck: Move slab definition per Stephen Rothwell and kbuild test robot. ]
[ paulmck: Handle CONFIG_MMU=n case where vmalloc() is kmalloc(). ]
[ paulmck: Apply Vlastimil Babka feedback on slab.c kmem_provenance(). ]
[ paulmck: Extract more info from !SLUB_DEBUG per Joonsoo Kim. ]
[ paulmck: Explicitly check for small pointers per Naresh Kamboju. ]
Acked-by: Joonsoo Kim 
Acked-by: Vlastimil Babka 
Tested-by: Naresh Kamboju 
Signed-off-by: Paul E. McKenney

mm: introduce vma_set_file function v5

2020-11-19T09:36:36+00:00

Add the new vma_set_file() function to allow changing
vma->vm_file with the necessary refcount dance.

v2: add more users of this.
v3: add missing EXPORT_SYMBOL, rebase on mmap cleanup,
    add comments why we drop the reference on two occasions.
v4: make it clear that changing an anonymous vma is illegal.
v5: move vma_set_file to mm/util.c

Signed-off-by: Christian König 
Reviewed-by: Daniel Vetter  (v2)
Reviewed-by: Jason Gunthorpe 
Acked-by: Andrew Morton 
Link: https://patchwork.freedesktop.org/patch/399360/

mm/util.c: update the kerneldoc for kstrdup_const()

2020-10-16T18:11:17+00:00

Memory allocated with kstrdup_const() must not be passed to regular
krealloc() as it is not aware of the possibility of the chunk residing in
.rodata.  Since there are no potential users of krealloc_const() at the
moment, let's just update the doc to make it explicit.

Signed-off-by: Bartosz Golaszewski 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200817173927.23389-1-brgl@bgdev.pl
Signed-off-by: Linus Torvalds