Kernel sources for Moto G9 (Play) (Guamp)
fd9fd8a9b3
commit 34b1a1ce1458f50ef27c54e28eb9b1947012907a upstream fixup_pi_state_owner() tries to ensure that the state of the rtmutex, pi_state and the user space value related to the PI futex are consistent before returning to user space. In case that the user space value update faults and the fault cannot be resolved by faulting the page in via fault_in_user_writeable() the function returns with -EFAULT and leaves the rtmutex and pi_state owner state inconsistent. A subsequent futex_unlock_pi() operates on the inconsistent pi_state and releases the rtmutex despite not owning it which can corrupt the RB tree of the rtmutex and cause a subsequent kernel stack use after free. It was suggested to loop forever in fixup_pi_state_owner() if the fault cannot be resolved, but that results in runaway tasks which is especially undesired when the problem happens due to a programming error and not due to malice. As the user space value cannot be fixed up, the proper solution is to make the rtmutex and the pi_state consistent so both have the same owner. This leaves the user space value out of sync. Any subsequent operation on the futex will fail because the 10th rule of PI futexes (pi_state owner and user space value are consistent) has been violated. As a consequence this removes the inept attempts of 'fixing' the situation in case that the current task owns the rtmutex when returning with an unresolvable fault by unlocking the rtmutex which left pi_state::owner and rtmutex::owner out of sync in a different and only slightly less dangerous way. Change-Id: Ic19f2e16d6de16db63594706eae5f547e38ea852 Fixes: |
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| android | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| techpack | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| Android.bp | ||
| AndroidKernel.mk | ||
| build.config.aarch64 | ||
| build.config.allmodconfig | ||
| build.config.allmodconfig.aarch64 | ||
| build.config.allmodconfig.arm | ||
| build.config.allmodconfig.x86_64 | ||
| build.config.arm | ||
| build.config.common | ||
| build.config.gki | ||
| build.config.gki-debug.aarch64 | ||
| build.config.gki-debug.x86_64 | ||
| build.config.gki.aarch64 | ||
| build.config.gki.x86_64 | ||
| build.config.gki_kasan | ||
| build.config.gki_kasan.aarch64 | ||
| build.config.gki_kasan.x86_64 | ||
| build.config.goldfish.arm | ||
| build.config.goldfish.arm64 | ||
| build.config.goldfish.mips | ||
| build.config.goldfish.mips64 | ||
| build.config.goldfish.x86 | ||
| build.config.goldfish.x86_64 | ||
| build.config.x86_64 | ||
| COPYING | ||
| CREDITS | ||
| gen_headers_arm.bp | ||
| gen_headers_arm64.bp | ||
| Kbuild | ||
| Kconfig | ||
| kernel_headers.py | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
| verity_dev_keys.x509 | ||
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.
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.