Fork of reMarkable kernel https://github.com/reMarkable/linux
8c2eb7b646
Add devm_free_irq() call to mlxreg-hotplug remove() for clean release
of devices irq resource. Fix debugobjects warning triggered by rmmod
It prevents of use-after-free memory, related to
mlxreg_hotplug_work_handler.
Issue has been reported as debugobjects warning triggered by
'rmmod mlxtreg-hotplug' flow, while running kernel with
CONFIG_DEBUG_OBJECTS* options.
[ 2489.623551] ODEBUG: free active (active state 0) object type: work_struct hint: mlxreg_hotplug_work_handler+0x0/0x7f0 [mlxreg_hotplug]
[ 2489.637097] WARNING: CPU: 5 PID: 3924 at lib/debugobjects.c:328 debug_print_object+0xfe/0x180
[ 2489.637165] RIP: 0010:debug_print_object+0xfe/0x180
?
[ 2489.637214] Call Trace:
[ 2489.637225] __debug_check_no_obj_freed+0x25e/0x320
[ 2489.637231] kfree+0x82/0x110
[ 2489.637238] release_nodes+0x33c/0x4e0
[ 2489.637242] ? devres_remove_group+0x1b0/0x1b0
[ 2489.637247] device_release_driver_internal+0x146/0x270
[ 2489.637251] driver_detach+0x73/0xe0
[ 2489.637254] bus_remove_driver+0xa1/0x170
[ 2489.637261] __x64_sys_delete_module+0x29e/0x320
[ 2489.637265] ? __ia32_sys_delete_module+0x320/0x320
[ 2489.637268] ? blkcg_exit_queue+0x20/0x20
[ 2489.637273] ? task_work_run+0x7d/0x100
[ 2489.637278] ? exit_to_usermode_loop+0x5b/0xf0
[ 2489.637281] do_syscall_64+0x73/0x160
[ 2489.637287] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 2489.637290] RIP: 0033:0x7f95c3596fd7
The difference in release flow with and with no devm_free_irq is listed
below:
bus: 'platform': remove driver mlxreg-hotplug
mlxreg_hotplug_remove(start)
-> devm_free_irq (with new code)
mlxreg_hotplug_remove (end)
release_nodes (start)
mlxreg-hotplug: DEVRES REL devm_hwmon_release (8 bytes)
device: 'hwmon3': device_unregister
PM: Removing info for No Bus:hwmon3
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (88 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (6 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_irq_release (16 bytes) (no new code)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (1376 bytes)
------------[ cut here ]------------ (no new code):
ODEBUG: free active (active state 0) object type: work_struct hint: mlxreg_hotplug_work_handler
release_nodes(end)
driver: 'mlxreg-hotplug': driver_release
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.