I completely missed the verification ping here in the sea of other kernel bug mail that I get. Will work with the LP team to get this verified as quickly as I can, but if you need to make a revert/ship call before I can, the patches should be pretty harmless even if they don't fix the bug, so I'd vote for keep and ship and we can fix later if we missed a bit.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1844155 Title: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes Status in linux package in Ubuntu: Confirmed Status in linux source package in Xenial: Fix Committed Status in linux package in Debian: Fix Released Bug description: [Impact] The arm64 kernel allows one to run aarch32 processes on an aarch64 processor, using the standard 32/64-bit syscall compatibility. However this compat layer does not correctly validate the arguments of the sigaltstack syscall which can result in process failures. [Test Case] The simple reproducer from https://bugs.debian.org/cgi- bin/bugreport.cgi?bug=904385 triggers a memory allocation error with the current Xenial 4.4 kernel. [Fix] Backport the following two upstream commits: 24951465cbd2 arm64: compat: Provide definition for COMPAT_SIGMINSTKSZ 22839869f21a signal: Introduce COMPAT_SIGMINSTKSZ for use in compat_sys_sigaltstack With these two commits, the reproducer no longer fails. [Regression Potential] Low. the modifications are trivial and the two patches have been in upstream for quite a while. [Original Description] This seems to have been fixed in 4.15 (finally), but is still an issue in the 4.4 kernel used on our builders, and possibly others as well (needs investigation). The original Debian bug report linked has more info, as well as the patchset on lkml at https://lkml.org/lkml/2018/7/25/409 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1844155/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
