linux-toradex.git/lib/assoc_array.c, branch v7.0-rc6 Linux kernel for Apalis and Colibri modules Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-22T04:03:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-22T04:03:00+00:00 32a92f8c89326985e05dce8b22d3f0aa07a3e1bd This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This converts some of the visually simpler cases that have been split
over multiple lines.  I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.

Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script.  I probably had made it a bit _too_ trivial.

So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.

The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-22T01:09:51+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-22T01:06:51+00:00 323bbfcf1ef8836d0d2ad9e2c1f1c684f0e3b5b3 This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.

As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-22T01:09:51+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-22T00:37:42+00:00 bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43 This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21T09:02:28+00:00 Kees Cook kees@kernel.org 2026-02-21T07:49:23+00:00 69050f8d6d075dc01af7a5f2f550a8067510366f This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org> 
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
assoc_array: fix the return value in assoc_array_insert_mid_shortcut() 2024-03-12T20:09:23+00:00 Roman Smirnov r.smirnov@omp.ru 2024-03-07T07:17:17+00:00 bea0a58695870295a315cec15a9fea6f40fe5ff3 Returning the edit variable is redundant because it is dereferenced right before it is returned. It would be better to return true. Found by Linux Verification Center (linuxtesting.org) with Svace. Link: https://lkml.kernel.org/r/20240307071717.5318-1-r.smirnov@omp.ru Signed-off-by: Roman Smirnov <r.smirnov@omp.ru> Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Returning the edit variable is redundant because it is dereferenced right
before it is returned.  It would be better to return true.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Link: https://lkml.kernel.org/r/20240307071717.5318-1-r.smirnov@omp.ru
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
assoc_array: Fix BUG_ON during garbage collect 2022-06-02T01:29:06+00:00 Stephen Brennan stephen.s.brennan@oracle.com 2022-05-19T08:50:30+00:00 d1dc87763f406d4e67caf16dbe438a5647692395 A rare BUG_ON triggered in assoc_array_gc: [3430308.818153] kernel BUG at lib/assoc_array.c:1609! Which corresponded to the statement currently at line 1593 upstream: BUG_ON(assoc_array_ptr_is_meta(p)); Using the data from the core dump, I was able to generate a userspace reproducer[1] and determine the cause of the bug. [1]: https://github.com/brenns10/kernel_stuff/tree/master/assoc_array_gc After running the iterator on the entire branch, an internal tree node looked like the following: NODE (nr_leaves_on_branch: 3) SLOT [0] NODE (2 leaves) SLOT [1] NODE (1 leaf) SLOT [2..f] NODE (empty) In the userspace reproducer, the pr_devel output when compressing this node was: -- compress node 0x5607cc089380 -- free=0, leaves=0 [0] retain node 2/1 [nx 0] [1] fold node 1/1 [nx 0] [2] fold node 0/1 [nx 2] [3] fold node 0/2 [nx 2] [4] fold node 0/3 [nx 2] [5] fold node 0/4 [nx 2] [6] fold node 0/5 [nx 2] [7] fold node 0/6 [nx 2] [8] fold node 0/7 [nx 2] [9] fold node 0/8 [nx 2] [10] fold node 0/9 [nx 2] [11] fold node 0/10 [nx 2] [12] fold node 0/11 [nx 2] [13] fold node 0/12 [nx 2] [14] fold node 0/13 [nx 2] [15] fold node 0/14 [nx 2] after: 3 At slot 0, an internal node with 2 leaves could not be folded into the node, because there was only one available slot (slot 0). Thus, the internal node was retained. At slot 1, the node had one leaf, and was able to be folded in successfully. The remaining nodes had no leaves, and so were removed. By the end of the compression stage, there were 14 free slots, and only 3 leaf nodes. The tree was ascended and then its parent node was compressed. When this node was seen, it could not be folded, due to the internal node it contained. The invariant for compression in this function is: whenever nr_leaves_on_branch < ASSOC_ARRAY_FAN_OUT, the node should contain all leaf nodes. The compression step currently cannot guarantee this, given the corner case shown above. To fix this issue, retry compression whenever we have retained a node, and yet nr_leaves_on_branch < ASSOC_ARRAY_FAN_OUT. This second compression will then allow the node in slot 1 to be folded in, satisfying the invariant. Below is the output of the reproducer once the fix is applied: -- compress node 0x560e9c562380 -- free=0, leaves=0 [0] retain node 2/1 [nx 0] [1] fold node 1/1 [nx 0] [2] fold node 0/1 [nx 2] [3] fold node 0/2 [nx 2] [4] fold node 0/3 [nx 2] [5] fold node 0/4 [nx 2] [6] fold node 0/5 [nx 2] [7] fold node 0/6 [nx 2] [8] fold node 0/7 [nx 2] [9] fold node 0/8 [nx 2] [10] fold node 0/9 [nx 2] [11] fold node 0/10 [nx 2] [12] fold node 0/11 [nx 2] [13] fold node 0/12 [nx 2] [14] fold node 0/13 [nx 2] [15] fold node 0/14 [nx 2] internal nodes remain despite enough space, retrying -- compress node 0x560e9c562380 -- free=14, leaves=1 [0] fold node 2/15 [nx 0] after: 3 Changes ======= DH: - Use false instead of 0. - Reorder the inserted lines in a couple of places to put retained before next_slot. ver #2) - Fix typo in pr_devel, correct comparison to "<=" Fixes: 3cb989501c26 ("Add a generic associative array implementation.") Cc: <stable@vger.kernel.org> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Andrew Morton <akpm@linux-foundation.org> cc: keyrings@vger.kernel.org Link: https://lore.kernel.org/r/20220511225517.407935-1-stephen.s.brennan@oracle.com/ # v1 Link: https://lore.kernel.org/r/20220512215045.489140-1-stephen.s.brennan@oracle.com/ # v2 Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
A rare BUG_ON triggered in assoc_array_gc:

    [3430308.818153] kernel BUG at lib/assoc_array.c:1609!

Which corresponded to the statement currently at line 1593 upstream:

    BUG_ON(assoc_array_ptr_is_meta(p));

Using the data from the core dump, I was able to generate a userspace
reproducer[1] and determine the cause of the bug.

[1]: https://github.com/brenns10/kernel_stuff/tree/master/assoc_array_gc

After running the iterator on the entire branch, an internal tree node
looked like the following:

    NODE (nr_leaves_on_branch: 3)
      SLOT [0] NODE (2 leaves)
      SLOT [1] NODE (1 leaf)
      SLOT [2..f] NODE (empty)

In the userspace reproducer, the pr_devel output when compressing this
node was:

    -- compress node 0x5607cc089380 --
    free=0, leaves=0
    [0] retain node 2/1 [nx 0]
    [1] fold node 1/1 [nx 0]
    [2] fold node 0/1 [nx 2]
    [3] fold node 0/2 [nx 2]
    [4] fold node 0/3 [nx 2]
    [5] fold node 0/4 [nx 2]
    [6] fold node 0/5 [nx 2]
    [7] fold node 0/6 [nx 2]
    [8] fold node 0/7 [nx 2]
    [9] fold node 0/8 [nx 2]
    [10] fold node 0/9 [nx 2]
    [11] fold node 0/10 [nx 2]
    [12] fold node 0/11 [nx 2]
    [13] fold node 0/12 [nx 2]
    [14] fold node 0/13 [nx 2]
    [15] fold node 0/14 [nx 2]
    after: 3

At slot 0, an internal node with 2 leaves could not be folded into the
node, because there was only one available slot (slot 0). Thus, the
internal node was retained. At slot 1, the node had one leaf, and was
able to be folded in successfully. The remaining nodes had no leaves,
and so were removed. By the end of the compression stage, there were 14
free slots, and only 3 leaf nodes. The tree was ascended and then its
parent node was compressed. When this node was seen, it could not be
folded, due to the internal node it contained.

The invariant for compression in this function is: whenever
nr_leaves_on_branch < ASSOC_ARRAY_FAN_OUT, the node should contain all
leaf nodes. The compression step currently cannot guarantee this, given
the corner case shown above.

To fix this issue, retry compression whenever we have retained a node,
and yet nr_leaves_on_branch < ASSOC_ARRAY_FAN_OUT. This second
compression will then allow the node in slot 1 to be folded in,
satisfying the invariant. Below is the output of the reproducer once the
fix is applied:

    -- compress node 0x560e9c562380 --
    free=0, leaves=0
    [0] retain node 2/1 [nx 0]
    [1] fold node 1/1 [nx 0]
    [2] fold node 0/1 [nx 2]
    [3] fold node 0/2 [nx 2]
    [4] fold node 0/3 [nx 2]
    [5] fold node 0/4 [nx 2]
    [6] fold node 0/5 [nx 2]
    [7] fold node 0/6 [nx 2]
    [8] fold node 0/7 [nx 2]
    [9] fold node 0/8 [nx 2]
    [10] fold node 0/9 [nx 2]
    [11] fold node 0/10 [nx 2]
    [12] fold node 0/11 [nx 2]
    [13] fold node 0/12 [nx 2]
    [14] fold node 0/13 [nx 2]
    [15] fold node 0/14 [nx 2]
    internal nodes remain despite enough space, retrying
    -- compress node 0x560e9c562380 --
    free=14, leaves=1
    [0] fold node 2/15 [nx 0]
    after: 3

Changes
=======
DH:
 - Use false instead of 0.
 - Reorder the inserted lines in a couple of places to put retained before
   next_slot.

ver #2)
 - Fix typo in pr_devel, correct comparison to "<="

Fixes: 3cb989501c26 ("Add a generic associative array implementation.")
Cc: <stable@vger.kernel.org>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/20220511225517.407935-1-stephen.s.brennan@oracle.com/ # v1
Link: https://lore.kernel.org/r/20220512215045.489140-1-stephen.s.brennan@oracle.com/ # v2
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
assoc_array: Avoid open coded arithmetic in allocator arguments 2021-10-13T19:54:13+00:00 Len Baker len.baker@gmx.com 2021-09-19T11:09:13+00:00 2a12e0003580505b8e7d82f9a8fef95f4a1031a8 As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors. So, use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the kmalloc() and kzalloc() functions. Also, take the opportunity to refactor the memcpy() calls to use the struct_size() and flex_array_size() helpers. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Signed-off-by: Len Baker <len.baker@gmx.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> 
As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, use the struct_size() helper to do the arithmetic instead of the
argument "size + count * size" in the kmalloc() and kzalloc() functions.

Also, take the opportunity to refactor the memcpy() calls to use the
struct_size() and flex_array_size() helpers.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Signed-off-by: Len Baker <len.baker@gmx.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Revert "lib: Revert use of fallthrough pseudo-keyword in lib/" 2020-11-18T20:15:17+00:00 Nick Desaulniers ndesaulniers@google.com 2020-11-16T04:35:31+00:00 4c1ca831adb1010e473a18eb01b3fbef7595f230 This reverts commit 6a9dc5fd6170 ("lib: Revert use of fallthrough pseudo-keyword in lib/") Now that we can build arch/powerpc/boot/ free of -Wimplicit-fallthrough, re-enable these fixes for lib/. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/236 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> 
This reverts commit 6a9dc5fd6170 ("lib: Revert use of fallthrough
pseudo-keyword in lib/")

Now that we can build arch/powerpc/boot/ free of -Wimplicit-fallthrough,
re-enable these fixes for lib/.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/236
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
lib: Revert use of fallthrough pseudo-keyword in lib/ 2020-08-24T21:17:44+00:00 Gustavo A. R. Silva gustavoars@kernel.org 2020-08-24T20:36:14+00:00 6a9dc5fd6170d0a41c8a14eb19e63d94bea5705a The following build error for powerpc64 was reported by Nathan Chancellor: "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage ... In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234, from arch/powerpc/boot/decompress.c:38: arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main': arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function) 586 | fallthrough; | ^~~~~~~~~~~ This will end up affecting distribution configurations such as Debian and OpenSUSE according to my testing. I am not sure what the solution is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure that compiler_attributes.h can be safely included." In order to avoid these sort of problems, it seems that the best solution is to use /* fall through */ comments instead of the fallthrough pseudo-keyword macro in lib/, for now. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The following build error for powerpc64 was reported by Nathan Chancellor:

  "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ

   $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage
   ...
   In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234,
                    from arch/powerpc/boot/decompress.c:38:
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main':
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function)
     586 |    fallthrough;
         |    ^~~~~~~~~~~

   This will end up affecting distribution configurations such as Debian
   and OpenSUSE according to my testing. I am not sure what the solution
   is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure
   that compiler_attributes.h can be safely included."

In order to avoid these sort of problems, it seems that the best
solution is to use /* fall through */ comments instead of the
fallthrough pseudo-keyword macro in lib/, for now.

Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
treewide: Use fallthrough pseudo-keyword 2020-08-23T22:36:59+00:00 Gustavo A. R. Silva gustavoars@kernel.org 2020-08-23T22:36:59+00:00 df561f6688fef775baa341a0f5d960becd248b11 Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> 
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>