This is my attempt to sort out the ABI issues with SIGTRAP TRAP_PERF before any userspace code starts using the new ABI. The big ideas are: - Placing the asserts first to prevent unexpected ABI changes - si_trapno can become an ordinary fault subfield. - Reworking siginfo so that si_perf_data can be a 64bit field. - struct signalfd_siginfo is almost full Marco I have incorporated your static_assert changes and built on them to prevent having unexpected ABI changes. The field si_trapno is changed to become an ordinary extension of the _sigfault member of siginfo. The code is refactored a bit and then si_perf_data is made a 64bit, and si_perf_type is made distinct from si_errno. Finally the signalfd_siginfo fields are removed as they appear to be filling up the structure without userspace actually being able to use them. v1: https://lkml.kernel.org/r/m1zgxfs7zq.fsf_-_@xxxxxxxxxxxxxxxxx Eric W. Biederman (9): siginfo: Move si_trapno inside the union inside _si_fault signal: Implement SIL_FAULT_TRAPNO signal: Use dedicated helpers to send signals with si_trapno set signal: Remove __ARCH_SI_TRAPNO signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency signal: Factor force_sig_perf out of perf_sigtrap signal: Redefine signinfo so 64bit fields are possible signal: Deliver all of the siginfo perf data in _perf signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo Marco Elver (3): sparc64: Add compile-time asserts for siginfo_t offsets arm: Add compile-time asserts for siginfo_t offsets arm64: Add compile-time asserts for siginfo_t offsets arch/alpha/include/uapi/asm/siginfo.h | 2 - arch/alpha/kernel/osf_sys.c | 2 +- arch/alpha/kernel/signal.c | 4 +- arch/alpha/kernel/traps.c | 24 ++--- arch/alpha/mm/fault.c | 4 +- arch/arm/kernel/signal.c | 37 +++++++ arch/arm64/kernel/signal.c | 37 +++++++ arch/arm64/kernel/signal32.c | 37 +++++++ arch/mips/include/uapi/asm/siginfo.h | 2 - arch/sparc/include/uapi/asm/siginfo.h | 3 - arch/sparc/kernel/process_64.c | 2 +- arch/sparc/kernel/signal32.c | 35 +++++++ arch/sparc/kernel/signal_64.c | 34 +++++++ arch/sparc/kernel/sys_sparc_32.c | 2 +- arch/sparc/kernel/sys_sparc_64.c | 2 +- arch/sparc/kernel/traps_32.c | 22 ++-- arch/sparc/kernel/traps_64.c | 44 ++++---- arch/sparc/kernel/unaligned_32.c | 2 +- arch/sparc/mm/fault_32.c | 2 +- arch/sparc/mm/fault_64.c | 2 +- arch/x86/kernel/signal_compat.c | 20 ++-- fs/signalfd.c | 23 ++--- include/linux/compat.h | 38 ++++--- include/linux/sched/signal.h | 13 +-- include/linux/signal.h | 3 +- include/uapi/asm-generic/siginfo.h | 57 +++++++---- include/uapi/linux/signalfd.h | 4 +- kernel/events/core.c | 11 +- kernel/signal.c | 113 +++++++++++++-------- .../selftests/perf_events/sigtrap_threads.c | 12 +-- 30 files changed, 402 insertions(+), 191 deletions(-)