5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric W. Biederman ebiederm@xmission.com
commit a3616a3c02722d1edb95acc7fceade242f6553ba upstream.
In the fpsp040 code when copyin or copyout fails call force_sigsegv(SIGSEGV) instead of do_exit(SIGSEGV).
This solves a couple of problems. Because do_exit embeds the ptrace stop PTRACE_EVENT_EXIT a complete stack frame needs to be present for that to work correctly. There is always the information needed for a ptrace stop where get_signal is called. So exiting with a signal solves the ptrace issue.
Further exiting with a signal ensures that all of the threads in a process are killed not just the thread that malfunctioned. Which avoids confusing userspace.
To make force_sigsegv(SIGSEGV) work in fpsp040_die modify the code to save all of the registers and jump to ret_from_exception (which ultimately calls get_signal) after fpsp040_die returns.
v2: Updated the branches to use gas's pseudo ops that automatically calculate the best branch instruction to use for the purpose.
v1: https://lkml.kernel.org/r/87a6m8kgtx.fsf_-_@disp2133 Link: https://lkml.kernel.org/r/87tukghjfs.fsf_-_@disp2133 Acked-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Finn Thain fthain@linux-m68k.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/m68k/fpsp040/skeleton.S | 3 ++- arch/m68k/kernel/traps.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)
--- a/arch/m68k/fpsp040/skeleton.S +++ b/arch/m68k/fpsp040/skeleton.S @@ -502,7 +502,8 @@ in_ea: .section .fixup,"ax" .even 1: - jbra fpsp040_die + jbsr fpsp040_die + jbra .Lnotkern
.section __ex_table,"a" .align 4 --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -1155,7 +1155,7 @@ asmlinkage void set_esp0(unsigned long s */ asmlinkage void fpsp040_die(void) { - do_exit(SIGSEGV); + force_sigsegv(SIGSEGV); }
#ifdef CONFIG_M68KFPU_EMU