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0d7b8855a0
Reported by Anton as LTP:munmap01 failing with Illegal Instruction
Exception.
--------------------->8--------------------------------------
mmap2(NULL, 24576, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x200d2000
munmap(0x200d2000, 24576) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x200d2000}
---
potentially unexpected fatal signal 4.
Path: /munmap01
CPU: 0 PID: 61 Comm: munmap01 Not tainted 3.13.0-g5d5c46d9a556 #8
task: 9f1a8000 ti: 9f154000 task.ti: 9f154000
[ECR ]: 0x00020100 => Illegal Insn
[EFA ]: 0x0001354c
[BLINK ]: 0x200515d4
[ERET ]: 0x1354c
@off 0x1354c in [/munmap01]
VMA: 0x00010000 to 0x00018000
[STAT32]: 0x800802c0
...
--------------------->8--------------------------------------
The issue was
1. munmap01 accessed unmapped memory (on purpose) with signal handler
installed for SIGSEGV
2. The faulting instruction happened to be in Delay Slot
00011864 <main>:
11908: bl.d 13284 <tst_resm>
1190c: stb r16,[r2]
3. kernel sets up the reg file for signal handler and correctly clears
the DE bit in pt_regs->status32 placeholder
4. However RESTORE_CALLEE_SAVED_USER macro is not adjusted for ARCv2,
and it over-writes the above with orig/stale value of status32
5. After RTIE, userspace signal handler executes a non branch
instruction with DE bit set, triggering Illegal Instruction Exception.
Reported-by: Anton Kolesov <akolesov@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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| .. | ||
| .gitignore | ||
| arc_hostlink.c | ||
| arcksyms.c | ||
| asm-offsets.c | ||
| clk.c | ||
| ctx_sw_asm.S | ||
| ctx_sw.c | ||
| devtree.c | ||
| disasm.c | ||
| entry-arcv2.S | ||
| entry-compact.S | ||
| entry.S | ||
| fpu.c | ||
| head.S | ||
| intc-arcv2.c | ||
| intc-compact.c | ||
| irq.c | ||
| kgdb.c | ||
| kprobes.c | ||
| Makefile | ||
| module.c | ||
| perf_event.c | ||
| process.c | ||
| ptrace.c | ||
| reset.c | ||
| setup.c | ||
| signal.c | ||
| smp.c | ||
| stacktrace.c | ||
| sys.c | ||
| time.c | ||
| traps.c | ||
| troubleshoot.c | ||
| unaligned.c | ||
| unwind.c | ||
| vmlinux.lds.S | ||