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Gustavo A. R. Silva d3204c0fdd net: sched: cls_u32: Fix allocation size in u32_init() 
[ Upstream commit c4d49196ceec80e30e8d981410d73331b49b7850 ]

commit d61491a51f ("net/sched: cls_u32: Replace one-element array
with flexible-array member") incorrecly replaced an instance of
`sizeof(*tp_c)` with `struct_size(tp_c, hlist->ht, 1)`. This results
in a an over-allocation of 8 bytes.

This change is wrong because `hlist` in `struct tc_u_common` is a
pointer:

net/sched/cls_u32.c:
struct tc_u_common {
        struct tc_u_hnode __rcu *hlist;
        void                    *ptr;
        int                     refcnt;
        struct idr              handle_idr;
        struct hlist_node       hnode;
        long                    knodes;
};

So, the use of `struct_size()` makes no sense: we don't need to allocate
any extra space for a flexible-array member. `sizeof(*tp_c)` is just fine.

So, `struct_size(tp_c, hlist->ht, 1)` translates to:

sizeof(*tp_c) + sizeof(tp_c->hlist->ht) ==
sizeof(struct tc_u_common) + sizeof(struct tc_u_knode *) ==
						144 + 8  == 0x98 (byes)
						     ^^^
						      |
						unnecessary extra
						allocation size

$ pahole -C tc_u_common net/sched/cls_u32.o
struct tc_u_common {
	struct tc_u_hnode *        hlist;                /*     0     8 */
	void *                     ptr;                  /*     8     8 */
	int                        refcnt;               /*    16     4 */

	/* XXX 4 bytes hole, try to pack */

	struct idr                 handle_idr;           /*    24    96 */
	/* --- cacheline 1 boundary (64 bytes) was 56 bytes ago --- */
	struct hlist_node          hnode;                /*   120    16 */
	/* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
	long int                   knodes;               /*   136     8 */

	/* size: 144, cachelines: 3, members: 6 */
	/* sum members: 140, holes: 1, sum holes: 4 */
	/* last cacheline: 16 bytes */
};

And with `sizeof(*tp_c)`, we have:

	sizeof(*tp_c) == sizeof(struct tc_u_common) == 144 == 0x90 (bytes)

which is the correct and original allocation size.

Fix this issue by replacing `struct_size(tp_c, hlist->ht, 1)` with
`sizeof(*tp_c)`, and avoid allocating 8 too many bytes.

The following difference in binary output is expected and reflects the
desired change:

| net/sched/cls_u32.o
| @@ -6148,7 +6148,7 @@
| include/linux/slab.h:599
|     2cf5:      mov    0x0(%rip),%rdi        # 2cfc <u32_init+0xfc>
|                        2cf8: R_X86_64_PC32     kmalloc_caches+0xc
|-    2cfc:      mov    $0x98,%edx
|+    2cfc:      mov    $0x90,%edx

Reported-by: Alejandro Colomar <alx@kernel.org>
Closes: https://lore.kernel.org/lkml/09b4a2ce-da74-3a19-6961-67883f634d98@kernel.org/
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-08 14:10:57 +01:00
arch sparc32: fix a braino in fault handling in csum_and_copy_..._user() 2023-11-02 09:35:32 +01:00
block blk-throttle: check for overflow in calculate_bytes_allowed 2023-11-02 09:35:29 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: lrw,xts - Replace strlcpy with strscpy 2023-09-23 11:11:01 +02:00
Documentation dt-bindings: mmc: sdhci-msm: correct minimum number of clocks 2023-10-25 12:03:13 +02:00
drivers coresight: tmc-etr: Disable warnings for allocation failures 2023-11-08 14:10:57 +01:00
fs ext4: avoid overlapping preallocations due to overflow 2023-11-02 09:35:32 +01:00
include kasan: print the original fault addr when access invalid shadow 2023-11-02 09:35:29 +01:00
init sched/psi: Select KERNFS as needed 2023-09-13 09:42:28 +02:00
io_uring io_uring/fdinfo: lock SQ thread while retrieving thread cpu/pid 2023-11-02 09:35:29 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel perf/core: Fix potential NULL deref 2023-11-02 09:35:32 +01:00
lib maple_tree: add GFP_KERNEL to allocations in mas_expected_entries() 2023-11-02 09:35:24 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm kasan: print the original fault addr when access invalid shadow 2023-11-02 09:35:29 +01:00
net net: sched: cls_u32: Fix allocation size in u32_init() 2023-11-08 14:10:57 +01:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples fprobe: Pass entry_data to handlers 2023-10-25 12:03:12 +02:00
scripts kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[] 2023-10-25 12:03:16 +02:00
security KEYS: trusted: Remove redundant static calls usage 2023-10-19 23:08:50 +02:00
sound ASoC: tlv320adc3xxx: BUG: Correct micbias setting 2023-11-08 14:10:57 +01:00
tools objtool/x86: add missing embedded_insn check 2023-11-02 09:35:33 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add() 2023-09-13 09:42:46 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS devlink: move code to a dedicated directory 2023-08-30 16:11:00 +02:00
Makefile Linux 6.1.61 2023-11-02 09:35:33 +01:00
README

README 

Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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