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Thursday, July 18th, 2019
| Time |
Event |
| 12:14a |
[$] LWN.net Weekly Edition for July 18, 2019
The LWN.net Weekly Edition for July 18, 2019 is available. | | 1:45p |
Security updates for Thursday
Security updates have been issued by Arch Linux (chromium, firefox, and squid), CentOS (thunderbird and vim), Debian (libonig), SUSE (firefox, glibc, kernel, libxslt, and tomcat), and Ubuntu (libreoffice and thunderbird). | | 6:35p |
[$] Kernel analysis with bpftrace At the 2019 Linux Storage, Filesystem,
and Memory-Management Summit (LSFMM) Brendan Gregg gave a keynote on BPF
observability that included a kernel issue he had debugged on Netflix
production servers using bpftrace. In this
article, he provides a
crash course on bpftrace for kernel developers—to help them more
easily analyze their code.
Subscribers can read on for a look at kernel analysis using
bpftrace from the upcoming weekly edition. | | 8:30p |
Cook: security things in Linux v5.2 Over on his blog, Kees Cook runs through the security changes that came in Linux 5.2. " While the SLUB and SLAB allocator freelists have been randomized for a while now, the overarching page allocator itself wasn’t. This meant that anything doing allocation outside of the kmem_cache/kmalloc() would have deterministic placement in memory. This is bad both for security and for some cache management cases. Dan Williams implemented this randomization under CONFIG_SHUFFLE_PAGE_ALLOCATOR now, which provides additional uncertainty to memory layouts, though at a rather low granularity of 4MB (see SHUFFLE_ORDER). Also note that this feature needs to be enabled at boot time with page_alloc.shuffle=1 unless you have direct-mapped memory-side-cache (you can check the state at /sys/module/page_alloc/parameters/shuffle)." |
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