mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-02-20 18:29:07 +07:00
10d0c768cc
The IRQ is requested before the struct rtc is allocated and registered, but this struct is used in the IRQ handler, leading to: Unable to handle kernel NULL pointer dereference at virtual address 0000017c pgd = a38a2f9b [0000017c] *pgd=00000000 Internal error: Oops: 5 [#1] ARM Modules linked in: CPU: 0 PID: 613 Comm: irq/48-m41t80 Not tainted 4.16.0-rc1+ #42 Hardware name: Atmel SAMA5 PC is at mutex_lock+0x14/0x38 LR is at m41t80_handle_irq+0x1c/0x9c pc : [<c06e864c>] lr : [<c04b70f0>] psr: 20000013 sp : dec73f30 ip : 00000000 fp : dec56d98 r10: df437cf0 r9 : c0a03008 r8 : c0145ffc r7 : df5c4300 r6 : dec568d0 r5 : df593000 r4 : 0000017c r3 : df592800 r2 : 60000013 r1 : df593000 r0 : 0000017c Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c53c7d Table: 20004059 DAC: 00000051 Process irq/48-m41t80 (pid: 613, stack limit = 0xb52d091e) Stack: (0xdec73f30 to 0xdec74000) 3f20: dec56840 df5c4300 00000001 df5c4300 3f40: c0145ffc c0146018 dec56840 ffffe000 00000001 c0146290 dec567c0 00000000 3f60: c0146084 ed7c9a62 c014615c dec56d80 dec567c0 00000000 dec72000 dec56840 3f80: c014615c c012ffc0 dec72000 dec567c0 c012fe80 00000000 00000000 00000000 3fa0: 00000000 00000000 00000000 c01010e8 00000000 00000000 00000000 00000000 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 29282726 2d2c2b2a [<c06e864c>] (mutex_lock) from [<c04b70f0>] (m41t80_handle_irq+0x1c/0x9c) [<c04b70f0>] (m41t80_handle_irq) from [<c0146018>] (irq_thread_fn+0x1c/0x54) [<c0146018>] (irq_thread_fn) from [<c0146290>] (irq_thread+0x134/0x1c0) [<c0146290>] (irq_thread) from [<c012ffc0>] (kthread+0x140/0x148) [<c012ffc0>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c) Exception stack(0xdec73fb0 to 0xdec73ff8) 3fa0: 00000000 00000000 00000000 00000000 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 Code: e3c33d7f e3c3303f f5d0f000 e593300c (e1901f9f) ---[ end trace 22b027302eb7c604 ]--- genirq: exiting task "irq/48-m41t80" (613) is an active IRQ thread (irq 48) Also, there is another possible race condition. The probe function is not allowed to fail after the RTC is registered because the following may happen: CPU0: CPU1: sys_load_module() do_init_module() do_one_initcall() cmos_do_probe() rtc_device_register() __register_chrdev() cdev->owner = struct module* open("/dev/rtc0") rtc_device_unregister() module_put() free_module() module_free(mod->module_core) /* struct module *module is now freed */ chrdev_open() spin_lock(cdev_lock) cdev_get() try_module_get() module_is_live() /* dereferences already freed struct module* */ Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc before requesting the IRQ and register it as late as possible. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.