Hi, First version of this series[1] was briefly in linux-next but had to be reverted due to a bug where schedule would end up being called while user_access was active[2].
After clarifications[3], rescheduling while in a user_access region is not allowed. * Patches 1 and 2 implement the unsafe accessors for arm64 * Patches 3 and 4 clarify this restriction in the API and attempts to check against violations of the restriction. Changes since v2[4]: - Rebase on v5.0-rc2 - access_ok() is now done in user_access_begin(), so rework accessors so access_ok() is not called in unsafe_get/put_user() - Split addition of unsafe accessors and the user_access_region check into separate patches - Avoid reading SCTLR_EL1 in user_access_region check - Add build option for user_access_region checking - Reword clarifications on unsafe accessors API Changes since v1[1]: - Add a way to detect code calling schedule within a user_access region - Make sure put_user/get_user arguments are evaluated before disabling PAN [1] https://www.spinics.net/lists/arm-kernel/msg674925.html [2] https://patchwork.kernel.org/patch/10634783/ [3] https://lkml.org/lkml/2018/11/28/50 [4] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-December/617080.html Cheers, Julien --> Julien Thierry (4): arm64: uaccess: Cleanup get/put_user() arm64: uaccess: Implement unsafe accessors uaccess: Check no rescheduling function is called in unsafe region arm64: uaccess: Implement user_access_region_active arch/arm64/include/asm/sysreg.h | 2 + arch/arm64/include/asm/uaccess.h | 123 ++++++++++++++++++++++++++------------- include/linux/kernel.h | 11 +++- include/linux/uaccess.h | 13 +++++ kernel/sched/core.c | 22 +++++++ lib/Kconfig.debug | 8 +++ 6 files changed, 135 insertions(+), 44 deletions(-) -- 1.9.1
