+ syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: arm: don't call addr_limit_user_check for nommu
has been added to the -mm tree.  Its filename is
     syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix.patch

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------------------------------------------------------
From: Christoph Hellwig <hch@lst.de>
Subject: arm: don't call addr_limit_user_check for nommu

On arm nommu kernel use the same constant for USER_DS and KERNEL_DS, and
seqment_eq always returns false.  With the current check in
addr_limit_user_check that works by accident, but when replacing
seqment_eq with uaccess_kerne it will fail.  Just remove the not needed
check entirely.

Link: http://lkml.kernel.org/r/20200721045834.GA9613@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/arm/kernel/signal.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/arm/kernel/signal.c~syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix
+++ a/arch/arm/kernel/signal.c
@@ -713,7 +713,9 @@ struct page *get_signal_page(void)
 /* Defer to generic check */
 asmlinkage void addr_limit_check_failed(void)
 {
+#ifdef CONFIG_MMU
 	addr_limit_user_check();
+#endif
 }
 
 #ifdef CONFIG_DEBUG_RSEQ
_

Patches currently in -mm which might be from hch@lst.de are

syscalls-use-uaccess_kernel-in-addr_limit_user_check.patch
syscalls-use-uaccess_kernel-in-addr_limit_user_check-fix.patch
nds32-use-uaccess_kernel-in-show_regs.patch
riscv-include-asm-pgtableh-in-asm-uaccessh.patch
uaccess-remove-segment_eq.patch
uaccess-add-force_uaccess_beginend-helpers.patch
uaccess-add-force_uaccess_beginend-helpers-v2.patch
exec-use-force_uaccess_begin-during-exec-and-exit.patch
kernel-add-a-kernel_wait-helper.patch