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| author | Al Viro <viro@zeniv.linux.org.uk> | 2023-01-30 23:48:54 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-03-02 12:30:08 -0500 |
| commit | bd75497a77ccae9a5e1b0f1a3fa8283d67b21f4c (patch) | |
| tree | 81397d2da394c3c03d59ce974611336f2f033d0c | |
| parent | c9c3395d5e3dcc6daee66c6908354d47bf98cb0c (diff) | |
| download | iio-bd75497a77ccae9a5e1b0f1a3fa8283d67b21f4c.tar.gz | |
m68k: fix livelock in uaccess
m68k equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling"
If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
to page tables. In such case we must *not* return to the faulting insn -
that would repeat the entire thing without making any progress; what we need
instead is to treat that as failed (user) memory access.
Tested-by: Finn Thain <fthain@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | arch/m68k/mm/fault.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 4d2837eb3e2a3e..228128e45c673b 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -138,8 +138,11 @@ good_area: fault = handle_mm_fault(vma, address, flags, regs); pr_debug("handle_mm_fault returns %x\n", fault); - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + goto no_context; return 0; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED) |