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authorAl Viro <viro@zeniv.linux.org.uk>2023-01-30 23:48:54 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2023-03-02 12:30:08 -0500
commitbd75497a77ccae9a5e1b0f1a3fa8283d67b21f4c (patch)
tree81397d2da394c3c03d59ce974611336f2f033d0c /arch/m68k
parentc9c3395d5e3dcc6daee66c6908354d47bf98cb0c (diff)
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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>
Diffstat (limited to 'arch/m68k')
-rw-r--r--arch/m68k/mm/fault.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 4d2837eb3e2a..228128e45c67 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)