Messages in this thread | | | From | Mark Rutland <> | Subject | [PATCH v2 0/9] thread_info: use helpers to snapshot thread flags | Date | Mon, 21 Jun 2021 10:05:52 +0100 |
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As thread_info::flags scan be manipulated by remote threads, it is necessary to use atomics or READ_ONCE() to ensure that code manipulates a consistent snapshot, but we open-code plain accesses to thread_info::flags across the kernel tree.
Generally we get away with this, but tools like KCSAN legitimately warn that there is a data-race, and this is potentially fragile with compiler optimizations, LTO, etc.
These patches introduce new helpers to snahpshot the thread flags, with the intent being that these should replace all plain accesses.
Since v1 [1]: * Drop RFC * Make read_ti_thread_flags() __always_inline * Clarify commit messages * Fix typo in arm64 patch * Accumulate Reviewed-by / Acked-by tags * Drop powerpc patch to avoid potential conflicts (per [2])
[1] https://lore.kernel.org/r/20210609122001.18277-1-mark.rutland@arm.com [2] https://lore.kernel.org/r/87k0mvtgeb.fsf@mpe.ellerman.id.au
Thanks, Mark.
Mark Rutland (9): thread_info: add helpers to snapshot thread flags entry: snapshot thread flags sched: snapshot thread flags alpha: snapshot thread flags arm: snapshot thread flags arm64: snapshot thread flags microblaze: snapshot thread flags openrisc: snapshot thread flags x86: snapshot thread flags
arch/alpha/kernel/signal.c | 2 +- arch/arm/kernel/signal.c | 2 +- arch/arm/mm/alignment.c | 2 +- arch/arm64/kernel/ptrace.c | 4 ++-- arch/arm64/kernel/signal.c | 2 +- arch/arm64/kernel/syscall.c | 4 ++-- arch/microblaze/kernel/signal.c | 2 +- arch/openrisc/kernel/signal.c | 2 +- arch/x86/kernel/process.c | 8 ++++---- arch/x86/kernel/process.h | 6 +++--- arch/x86/mm/tlb.c | 2 +- include/linux/entry-kvm.h | 2 +- include/linux/thread_info.h | 14 ++++++++++++++ kernel/entry/common.c | 4 ++-- kernel/entry/kvm.c | 4 ++-- kernel/sched/core.c | 2 +- 16 files changed, 38 insertions(+), 24 deletions(-)
-- 2.11.0
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