Messages in this thread | | | From | Mark Rutland <> | Subject | [PATCH v5 00/10] thread_info: use helpers to snapshot thread flags | Date | Tue, 14 Sep 2021 11:30:17 +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.
I've been assuming this would go via the TIP tree. TIP folk, are you happy to pick this up, or would you be happy to pick at least the first three patches which cover the core bits?
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])
Since v2 [3]: * Rebase to v5.14-rc1 * Reinstate powerpc patch
Since v3 [4]: * Rebase to v5.14-rc4
Since v4 [5]: * Rebase to v5.15-rc1 * Apply Acked-by / Tested-by tags
[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 [3] https://lore.kernel.org/r/20210621090602.16883-1-mark.rutland@arm.com [4] https://lore.kernel.org/r/20210713113842.2106-1-mark.rutland@arm.com [5] https://lore.kernel.org/r/20210803095428.17009-1-mark.rutland@arm.com
Thanks, Mark.
Mark Rutland (10): 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 powerpc: 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/entry-common.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/powerpc/kernel/interrupt.c | 13 ++++++------- arch/powerpc/kernel/ptrace/ptrace.c | 3 +-- 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 +- 19 files changed, 46 insertions(+), 34 deletions(-)
-- 2.11.0
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