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| author | Al Viro <viro@zeniv.linux.org.uk> | 2023-01-31 07:34:16 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-03-02 20:32:15 +0300 |
| commit | dce45493aff3fdd57fed2a0da264e585dba88433 (patch) | |
| tree | d1e462232cfc4a0a3b655d1c1cba4206d03a4db4 /arch/alpha | |
| parent | 15261678a8c2ff093ffedad730b1646d34a1716a (diff) | |
| download | linux-dce45493aff3fdd57fed2a0da264e585dba88433.tar.xz | |
alpha: fix livelock in uaccess
alpha 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>
Diffstat (limited to 'arch/alpha')
| -rw-r--r-- | arch/alpha/mm/fault.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index ef427a6bdd1a..7b01ae4f3bc6 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -152,8 +152,11 @@ retry: the fault. */ 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) |