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Cristian Marussi 91ff1e9652 firmware: arm_scmi: Balance device refcount when destroying devices 
[ Upstream commit 9ca67840c0 ]

Using device_find_child() to lookup the proper SCMI device to destroy
causes an unbalance in device refcount, since device_find_child() calls an
implicit get_device(): this, in turns, inhibits the call of the provided
release methods upon devices destruction.

As a consequence, one of the structures that is not freed properly upon
destruction is the internal struct device_private dev->p populated by the
drivers subsystem core.

KMemleak detects this situation since loading/unloding some SCMI driver
causes related devices to be created/destroyed without calling any
device_release method.

unreferenced object 0xffff00000f583800 (size 512):
  comm "insmod", pid 227, jiffies 4294912190
  hex dump (first 32 bytes):
    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........
    ff ff ff ff ff ff ff ff 60 36 1d 8a 00 80 ff ff  ........`6......
  backtrace (crc 114e2eed):
    kmemleak_alloc+0xbc/0xd8
    __kmalloc_cache_noprof+0x2dc/0x398
    device_add+0x954/0x12d0
    device_register+0x28/0x40
    __scmi_device_create.part.0+0x1bc/0x380
    scmi_device_create+0x2d0/0x390
    scmi_create_protocol_devices+0x74/0xf8
    scmi_device_request_notifier+0x1f8/0x2a8
    notifier_call_chain+0x110/0x3b0
    blocking_notifier_call_chain+0x70/0xb0
    scmi_driver_register+0x350/0x7f0
    0xffff80000a3b3038
    do_one_initcall+0x12c/0x730
    do_init_module+0x1dc/0x640
    load_module+0x4b20/0x5b70
    init_module_from_file+0xec/0x158

$ ./scripts/faddr2line ./vmlinux device_add+0x954/0x12d0
device_add+0x954/0x12d0:
kmalloc_noprof at include/linux/slab.h:901
(inlined by) kzalloc_noprof at include/linux/slab.h:1037
(inlined by) device_private_init at drivers/base/core.c:3510
(inlined by) device_add at drivers/base/core.c:3561

Balance device refcount by issuing a put_device() on devices found via
device_find_child().

Reported-by: Alice Ryhl <aliceryhl@google.com>
Closes: https://lore.kernel.org/linux-arm-kernel/Z8nK3uFkspy61yjP@arm.com/T/#mc1f73a0ea5e41014fa145147b7b839fc988ada8f
CC: Sudeep Holla <sudeep.holla@arm.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
Fixes: d4f9dddd21 ("firmware: arm_scmi: Add dynamic scmi devices creation")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Message-Id: <20250306185447.2039336-1-cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-05-09 09:39:41 +02:00
arch KVM: x86: Load DR6 with guest value only before entering .vcpu_run() loop 2025-05-09 09:39:37 +02:00
block blk-iocost: do not WARN if iocg was already offlined 2025-05-02 07:44:22 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: null - Use spin lock instead of mutex 2025-05-02 07:44:34 +02:00
Documentation scsi: libsas: Delete lldd_clear_aca callback 2025-05-02 07:44:07 +02:00
drivers firmware: arm_scmi: Balance device refcount when destroying devices 2025-05-09 09:39:41 +02:00
fs jfs: define xtree root and page independently 2025-05-02 07:44:39 +02:00
include xdp: Reset bpf_redirect_info before running a xdp's BPF prog. 2025-05-02 07:44:39 +02:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:44:36 +02:00
io_uring io_uring: fix possible deadlock in io_register_iowq_max_workers() 2024-11-17 15:06:25 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel tracing: Fix oob write in trace_seq_to_buffer() 2025-05-09 09:39:37 +02:00
lib ubsan: Fix panic from test_ubsan_out_of_bounds 2025-05-02 07:44:38 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: fix apply_to_existing_page_range() 2025-05-02 07:44:24 +02:00
net net: ipv6: fix UDPv6 GSO segmentation with NAT 2025-05-09 09:39:39 +02:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-03-13 12:49:57 +01:00
scripts selinux: Chain up tool resolving errors in install_policy.sh 2025-04-10 14:31:57 +02:00
security landlock: Add the errata interface 2025-05-02 07:44:20 +02:00
sound ALSA: usb-audio: Add second USB ID for Jabra Evolve 65 headset 2025-05-09 09:39:35 +02:00
tools selftests/mincore: Allow read-ahead pages to reach the end of the file 2025-05-02 07:44:37 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-10-22 15:40:41 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:11:10 +02:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS trace: Relocate event helper files 2024-04-10 16:19:24 +02:00
Makefile Linux 5.15.181 2025-05-02 07:44:40 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.