a230883688
It seems like other architectures, namely x86 and arm64 and riscv
at least, include the running function as top entry when saving
stack trace with save_stack_trace_regs().
Functionnalities like KFENCE expect it.
Do the same on powerpc, it allows KFENCE and other users to
properly identify the faulting function as depicted below.
Before the patch KFENCE was identifying finish_task_switch.isra
as the faulting function.
[ 14.937370] ==================================================================
[ 14.948692] BUG: KFENCE: invalid read in test_invalid_access+0x54/0x108
[ 14.948692]
[ 14.956814] Invalid read at 0xdf98800a:
[ 14.960664] test_invalid_access+0x54/0x108
[ 14.964876] finish_task_switch.isra.0+0x54/0x23c
[ 14.969606] kunit_try_run_case+0x5c/0xd0
[ 14.973658] kunit_generic_run_threadfn_adapter+0x24/0x30
[ 14.979079] kthread+0x15c/0x174
[ 14.982342] ret_from_kernel_thread+0x14/0x1c
[ 14.986731]
[ 14.988236] CPU: 0 PID: 111 Comm: kunit_try_catch Tainted: G B 5.12.0-rc1-01537-g95f6e2088d7e-dirty #4682
[ 14.999795] NIP: c016ec2c LR: c02f517c CTR: c016ebd8
[ 15.004851] REGS: e2449d90 TRAP: 0301 Tainted: G B (5.12.0-rc1-01537-g95f6e2088d7e-dirty)
[ 15.015274] MSR: 00009032 <EE,ME,IR,DR,RI> CR: 22000004 XER: 00000000
[ 15.022043] DAR: df98800a DSISR: 20000000
[ 15.022043] GPR00: c02f517c e2449e50 c1142080 e100dd24 c084b13c 00000008 c084b32b c016ebd8
[ 15.022043] GPR08: c0850000 df988000 c0d10000 e2449eb0 22000288
[ 15.040581] NIP [c016ec2c] test_invalid_access+0x54/0x108
[ 15.046010] LR [c02f517c] kunit_try_run_case+0x5c/0xd0
[ 15.051181] Call Trace:
[ 15.053637] [e2449e50] [c005a68c] finish_task_switch.isra.0+0x54/0x23c (unreliable)
[ 15.061338] [e2449eb0] [c02f517c] kunit_try_run_case+0x5c/0xd0
[ 15.067215] [e2449ed0] [c02f648c] kunit_generic_run_threadfn_adapter+0x24/0x30
[ 15.074472] [e2449ef0] [c004e7b0] kthread+0x15c/0x174
[ 15.079571] [e2449f30] [c001317c] ret_from_kernel_thread+0x14/0x1c
[ 15.085798] Instruction dump:
[ 15.088784] 8129d608 38e7ebd8 81020280 911f004c 39000000 995f0024 907f0028 90ff001c
[ 15.096613] 3949000a 915f0020 3d40c0d1 3d00c085 <8929000a> 3908adb0 812a4b98 3d40c02f
[ 15.104612] ==================================================================
Fixes:
|
||
|---|---|---|
| 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.