This series enhances the arm64 kernel's ability to recover from memory poison (hardware memory errors) encountered during common I/O and data copy operations. The work extends the existing RAS error handling framework to gracefully handle poison in scenarios that previously could lead to kernel panics or silent data corruption. Memory errors are increasingly common in large-scale deployments; recovering from them where possible improves system reliability and availability. The patches implement recovery in key paths such as copy_{from/to}_user, iov_iter, __kernel_read, and shmem_file_read_iter, ensuring that when poison is consumed, the kernel can either complete the operation safely (by returning an error) or deliver the appropriate signal to the affected user process. Additionally, the series refines the SEA (Synchronous External Abort) handling path: it moves siaddr extraction earlier for accurate signal info, adds RAS logging for better diagnostics, and ensures a SIGBUS is sent to user tasks when APEI claims fail. The series has been tested on ARM64 platforms with RAS capabilities, using error injection to verify that poison is correctly handled and that appropriate errors or signals are delivered. Feedback and review are appreciated. Linus Torvalds (1): iov_iter: get rid of 'copy_mc' flag Wupeng Ma (7): arm64: mm: support recovery from copy_{from/to}_user_page() iov_iter: add mc support for copy_page_to_iter arm64: fs: support poison recovery from __kernel_read() arm64: mm: shmem: support poison recovery from shmem_file_read_iter() arm64: move getting valid siaddr to the top of do_sea arm64: add ras log during do_sea arm64: send sig fault for user task when apei_claim_sea fails arch/arm64/include/asm/cacheflush.h | 7 +++++ arch/arm64/kernel/acpi.c | 2 ++ arch/arm64/mm/extable.c | 5 +++- arch/arm64/mm/fault.c | 46 ++++++++++++++++++++++------- arch/arm64/mm/flush.c | 11 +++++++ fs/coredump.c | 45 ++++++++++++++++++++++++++-- include/asm-generic/cacheflush.h | 24 +++++++++++++++ lib/iov_iter.c | 16 ++++++++-- mm/filemap.c | 3 ++ mm/memory.c | 15 +++++++--- mm/shmem.c | 4 +++ 11 files changed, 158 insertions(+), 20 deletions(-) -- 2.43.0