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| author | Al Viro <viro@zeniv.linux.org.uk> | 2023-01-30 23:52:40 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-03-02 12:32:44 -0500 |
| commit | caa82ae7ef52b7cf5f80a2b2fbcbdbcfd16426cc (patch) | |
| tree | fe59f45376e19cd3bcaa3e6362ff9a4216bbe3f4 /arch | |
| parent | e902e508c5b280488c62f119a05ad88f9f7eb1cb (diff) | |
| download | lwn-caa82ae7ef52b7cf5f80a2b2fbcbdbcfd16426cc.tar.gz lwn-caa82ae7ef52b7cf5f80a2b2fbcbdbcfd16426cc.zip | |
openrisc: fix livelock in uaccess
openrisc 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')
| -rw-r--r-- | arch/openrisc/mm/fault.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index b4762d66e9ef..6734fee3134f 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -162,8 +162,11 @@ 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) |