diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2023-01-30 23:51:40 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-03-02 12:32:35 -0500 |
| commit | e902e508c5b280488c62f119a05ad88f9f7eb1cb (patch) | |
| tree | f8825c6263cf820cb93b8869d5239d2e0f3ead91 | |
| parent | a1179ac743e8f2044b67848b5109614619b65366 (diff) | |
nios2: fix livelock in uaccess
nios2 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.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | arch/nios2/mm/fault.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index edaca0a6c1c1..ca64eccea551 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -136,8 +136,11 @@ good_area: */ fault = handle_mm_fault(vma, address, flags, regs); - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + goto no_context; return; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED) |