diff mbox series

[10/10] sparc: fix livelock in uaccess

Message ID Y9l09ZE7q0POyBC3@ZenIV (mailing list archive)
State Not Applicable
Headers show
Series [01/10] alpha: fix livelock in uaccess | expand

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Context Check Description
conchuod/cover_letter warning Series does not have a cover letter
conchuod/tree_selection success Guessed tree name to be for-next
conchuod/fixes_present success Fixes tag not required for -next series
conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 13 and now 13
conchuod/verify_signedoff success Signed-off-by tag matches author and committer
conchuod/kdoc success Errors and warnings before: 0 this patch: 0
conchuod/build_rv64_clang_allmodconfig success Errors and warnings before: 0 this patch: 0
conchuod/module_param success Was 0 now: 0
conchuod/build_rv64_gcc_allmodconfig success Errors and warnings before: 0 this patch: 0
conchuod/alphanumeric_selects success Out of order selects before the patch: 57 and now 57
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 2 this patch: 2
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch success total: 0 errors, 0 warnings, 0 checks, 26 lines checked
conchuod/source_inline success Was 0 now: 0
conchuod/build_rv64_nommu_k210_defconfig success Build OK
conchuod/verify_fixes success No Fixes tag
conchuod/build_rv64_nommu_virt_defconfig success Build OK

Commit Message

Al Viro Jan. 31, 2023, 8:07 p.m. UTC
sparc 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>
---
 arch/sparc/mm/fault_32.c | 5 ++++-
 arch/sparc/mm/fault_64.c | 7 ++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
index 91259f291c54..179295b14664 100644
--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -187,8 +187,11 @@  asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
 	 */
 	fault = handle_mm_fault(vma, address, flags, regs);
 
-	if (fault_signal_pending(fault, regs))
+	if (fault_signal_pending(fault, regs)) {
+		if (!from_user)
+			goto no_context;
 		return;
+	}
 
 	/* The fault is fully completed (including releasing mmap lock) */
 	if (fault & VM_FAULT_COMPLETED)
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
index 4acc12eafbf5..d91305de694c 100644
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -424,8 +424,13 @@  asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
 
 	fault = handle_mm_fault(vma, address, flags, regs);
 
-	if (fault_signal_pending(fault, regs))
+	if (fault_signal_pending(fault, regs)) {
+		if (regs->tstate & TSTATE_PRIV) {
+			insn = get_fault_insn(regs, insn);
+			goto handle_kernel_fault;
+		}
 		goto exit_exception;
+	}
 
 	/* The fault is fully completed (including releasing mmap lock) */
 	if (fault & VM_FAULT_COMPLETED)