0fdb64c2a3
When generating instructions at runtime, for example due to kernel text patching or the BPF JIT, we can emit a trapping BRK instruction if we are asked to encode an invalid instruction such as an out-of-range] branch. This is indicative of a bug in the caller, and will result in a crash on executing the generated code. Unfortunately, the message from the crash is really unhelpful, and mumbles something about ptrace: | Unexpected kernel BRK exception at EL1 | Internal error: ptrace BRK handler: f2000100 [#1] SMP We can do better than this. Install a break handler for FAULT_BRK_IMM, which is the immediate used to encode the "I've been asked to generate an invalid instruction" error, and triage the faulting PC to determine whether or not the failure occurred in the BPF JIT. Link: https://lore.kernel.org/r/20200915141707.GB26439@willie-the-truck Reported-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Will Deacon <will@kernel.org> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.