[PATCH 00/20] exit cleanups

Eric W. Biederman
2021-10-20T17:32:39Z

While looking at some issues related to the exit path in the kernel I
found several instances where the code is not using the existing
abstractions properly.

This set of changes introduces force_fatal_sig a way of sending
a signal and not allowing it to be caught, and corrects the
misuse of the existing abstractions that I found.

A lot of the misuse of the existing abstractions are silly things such
as doing something after calling a no return function, rolling BUG by
hand, doing more work than necessary to terminate a kernel thread, or
calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL).

It is my plan after sending all of these changes out for review to place
them in a topic branch for sending Linus. Especially for the changes
that depend upon the new helper force_fatal_sig this is important.

Eric W. Biederman (20):
exit/doublefault: Remove apparently bogus comment about rewind_stack_do_exit
exit: Remove calls of do_exit after noreturn versions of die
reboot: Remove the unreachable panic after do_exit in reboot(2)
signal/sparc32: Remove unreachable do_exit in do_sparc_fault
signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT
signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL)
signal/powerpc: On swapcontext failure force SIGSEGV
signal/sparc: In setup_tsb_params convert open coded BUG into BUG
signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON
signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.
signal/s390: Use force_sigsegv in default_trap_handler
exit/kthread: Have kernel threads return instead of calling do_exit
signal: Implement force_fatal_sig
exit/syscall_user_dispatch: Send ordinary signals on failure
signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails
signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig
signal/x86: In emulate_vsyscall force a signal instead of calling do_exit
exit/rtl8723bs: Replace the macro thread_exit with a simple return 0
exit/rtl8712: Replace the macro thread_exit with a simple return 0
exit/r8188eu: Replace the macro thread_exit with a simple return 0

arch/mips/kernel/r2300_fpu.S | 4 ++--
arch/mips/kernel/syscall.c | 9 --------
arch/nds32/kernel/traps.c | 2 +-
arch/nds32/mm/fault.c | 6 +----
arch/openrisc/kernel/traps.c | 2 +-
arch/openrisc/mm/fault.c | 4 +---
arch/powerpc/kernel/signal_32.c | 6 +++--
arch/powerpc/kernel/signal_64.c | 9 +++++---
arch/s390/include/asm/kdebug.h | 2 +-
arch/s390/kernel/dumpstack.c | 2 +-
arch/s390/kernel/traps.c | 2 +-
arch/s390/mm/fault.c | 2 --
arch/sh/kernel/cpu/fpu.c | 10 +++++----
arch/sh/kernel/traps.c | 2 +-
arch/sh/mm/fault.c | 2 --
arch/sparc/kernel/signal_32.c | 4 ++--
arch/sparc/kernel/windows.c | 6 +++--
arch/sparc/mm/fault_32.c | 1 -
arch/sparc/mm/tsb.c | 2 +-
arch/x86/entry/vsyscall/vsyscall_64.c | 3 ++-
arch/x86/kernel/doublefault_32.c | 3 ---
arch/x86/kernel/signal.c | 6 ++++-
arch/x86/kernel/vm86_32.c | 8 +++----
arch/xtensa/kernel/traps.c | 2 +-
arch/xtensa/mm/fault.c | 3 +--
drivers/firmware/stratix10-svc.c | 4 ++--
drivers/soc/ti/wkup_m3_ipc.c | 2 +-
drivers/staging/r8188eu/core/rtw_cmd.c | 2 +-
drivers/staging/r8188eu/core/rtw_mp.c | 2 +-
drivers/staging/r8188eu/include/osdep_service.h | 2 --
drivers/staging/rtl8712/osdep_service.h | 1 -
drivers/staging/rtl8712/rtl8712_cmd.c | 2 +-
drivers/staging/rtl8723bs/core/rtw_cmd.c | 2 +-
drivers/staging/rtl8723bs/core/rtw_xmit.c | 2 +-
drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c | 2 +-
.../rtl8723bs/include/osdep_service_linux.h | 2 --
fs/ocfs2/journal.c | 5 +----
include/linux/sched/signal.h | 1 +
kernel/entry/syscall_user_dispatch.c | 12 ++++++----
kernel/kthread.c | 2 +-
kernel/reboot.c | 1 -
kernel/signal.c | 26 ++++++++++++++--------
net/batman-adv/tp_meter.c | 2 +-
43 files changed, 83 insertions(+), 91 deletions(-)

Eric