5059353df8
dm-crypt consumes an excessive amount memory when the user attempts to zero a dm-crypt device with "blkdiscard -z". The command "blkdiscard -z" calls the BLKZEROOUT ioctl, it goes to the function __blkdev_issue_zeroout, __blkdev_issue_zeroout sends a large amount of write bios that contain the zero page as their payload. For each incoming page, dm-crypt allocates another page that holds the encrypted data, so when processing "blkdiscard -z", dm-crypt tries to allocate the amount of memory that is equal to the size of the device. This can trigger OOM killer or cause system crash. Fix this by limiting the amount of memory that dm-crypt allocates to 2% of total system memory. This limit is system-wide and is divided by the number of active dm-crypt devices and each device receives an equal share. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.