[LEDE-DEV] [PATCH] kernel: backport fix undefined abort

Tue Jan 30 07:32:56 PST 2018

Evgeniy Didin <Evgeniy.Didin at synopsys.com> wrote:

> While building mpi.ko module with stable Linux v4.14.14 an error occured:
> >ERROR: "abort" [lib/mpi/mpi.ko] undefined!
> In upstream Linux 4.15 this issue is fixed:
> Commit 7c2c11b208be ("arch: define weak abort()")
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c2c11b208be09c156573fc0076b7b3646e05219

> Commit dc8635b78cd8 ("kernel/exit.c: export abort() to modules")
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dc8635b78cd8669c37e230058d18c33af7451ab1

> So lets add backport patches until these fixes
> are not applied in stable version.

> Signed-off-by: Evgeniy Didin <Evgeniy.Didin at synopsys.com>
> Cc: Alexey Brodkin <abrodkin at synopsys.com>
> CC: John Crispin <john at phrozen.org>
> CC: Hauke Mehrtens <hauke at hauke-m.de>

Copy this description into commit comments. After next patch rebase - it lost.

> ---
>  .../080-v4.15-0001-arch-define-weak-abort.patch    | 51 +++++++++++++++
>  ...002-kernel-exit.c-export-abort-to-modules.patch | 74 ++++++++++++++++++++++
>  2 files changed, 125 insertions(+)
>  create mode 100644 target/linux/generic/backport-4.14/080-v4.15-0001-arch-define-weak-abort.patch
>  create mode 100644 target/linux/generic/backport-4.14/081-v4.15-0002-kernel-exit.c-export-abort-to-modules.patch

> diff --git a/target/linux/generic/backport-4.14/080-v4.15-0001-arch-define-weak-abort.patch b/target/linux/generic/backport-4.14/080-v4.15-0001-arch-define-weak-abort.patch
> new file mode 100644
> index 0000000000..2d247a39e4
> --- /dev/null
> +++ b/target/linux/generic/backport-4.14/080-v4.15-0001-arch-define-weak-abort.patch
> @@ -0,0 +1,51 @@
> +From 7c2c11b208be09c156573fc0076b7b3646e05219 Mon Sep 17 00:00:00 2001
> +From: Sudip Mukherjee <sudipm.mukherjee at gmail.com>
> +Date: Thu, 14 Dec 2017 15:33:19 -0800
> +Subject: [PATCH] arch: define weak abort()
> +
> +gcc toggle -fisolate-erroneous-paths-dereference (default at -O2
> +onwards) isolates faulty code paths such as null pointer access, divide
> +by zero etc.  If gcc port doesnt implement __builtin_trap, an abort() is
> +generated which causes kernel link error.
> +
> +In this case, gcc is generating abort due to 'divide by zero' in
> +lib/mpi/mpih-div.c.
> +
> +Currently 'frv' and 'arc' are failing.  Previously other arch was also
> +broken like m32r was fixed by commit d22e3d69ee1a ("m32r: fix build
> +failure").
> +
> +Let's define this weak function which is common for all arch and fix the
> +problem permanently.  We can even remove the arch specific 'abort' after
> +this is done.
> +
> +Link: http://lkml.kernel.org/r/1513118956-8718-1-git-send-email-sudipm.mukherjee@gmail.com
> +Signed-off-by: Sudip Mukherjee <sudipm.mukherjee at gmail.com>
> +Cc: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
> +Cc: Vineet Gupta <Vineet.Gupta1 at synopsys.com>
> +Cc: Sudip Mukherjee <sudipm.mukherjee at gmail.com>
> +Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> +Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> +---
> + kernel/exit.c | 8 ++++++++
> + 1 file changed, 8 insertions(+)
> +
> +diff --git a/kernel/exit.c b/kernel/exit.c
> +index 6b4298a41167..df0c91d5606c 100644
> +--- a/kernel/exit.c
> ++++ b/kernel/exit.c
> +@@ -1755,3 +1755,11 @@ COMPAT_SYSCALL_DEFINE5(waitid,
> +       return -EFAULT;
> + }
> + #endif
> ++
> ++__weak void abort(void)
> ++{
> ++      BUG();
> ++
> ++      /* if that doesn't kill us, halt */
> ++      panic("Oops failed to kill thread");
> ++}
> +-- 
> +2.11.0
> +
> diff --git a/target/linux/generic/backport-4.14/081-v4.15-0002-kernel-exit.c-export-abort-to-modules.patch b/target/linux/generic/backport-4.14/081-v4.15-0002-kernel-exit.c-export-abort-to-modules.patch
> new file mode 100644
> index 0000000000..5b95b6798d
> --- /dev/null
> +++ b/target/linux/generic/backport-4.14/081-v4.15-0002-kernel-exit.c-export-abort-to-modules.patch
> @@ -0,0 +1,74 @@
> +From dc8635b78cd8669c37e230058d18c33af7451ab1 Mon Sep 17 00:00:00 2001
> +From: Andrew Morton <akpm at linux-foundation.org>
> +Date: Thu, 4 Jan 2018 16:17:56 -0800
> +Subject: [PATCH] kernel/exit.c: export abort() to modules
> +
> +gcc -fisolate-erroneous-paths-dereference can generate calls to abort()
> +from modular code too.
> +
> +[arnd at arndb.de: drop duplicate exports of abort()]
> +  Link: http://lkml.kernel.org/r/20180102103311.706364-1-arnd@arndb.de
> +Reported-by: Vineet Gupta <Vineet.Gupta1 at synopsys.com>
> +Cc: Sudip Mukherjee <sudipm.mukherjee at gmail.com>
> +Cc: Arnd Bergmann <arnd at arndb.de>
> +Cc: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
> +Cc: Russell King <rmk+kernel at armlinux.org.uk>
> +Cc: Jose Abreu <Jose.Abreu at synopsys.com>
> +Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> +Signed-off-by: Arnd Bergmann <arnd at arndb.de>
> +Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> +---
> + arch/arm/kernel/traps.c       | 1 -
> + arch/m32r/kernel/traps.c      | 1 -
> + arch/unicore32/kernel/traps.c | 1 -
> + kernel/exit.c                 | 1 +
> + 4 files changed, 1 insertion(+), 3 deletions(-)
> +
> +diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> +index 5cf04888c581..3e26c6f7a191 100644
> +--- a/arch/arm/kernel/traps.c
> ++++ b/arch/arm/kernel/traps.c
> +@@ -793,7 +793,6 @@ void abort(void)
> +       /* if that doesn't kill us, halt */
> +       panic("Oops failed to kill thread");
> + }
> +-EXPORT_SYMBOL(abort);
> + 
> + void __init trap_init(void)
> + {
> +diff --git a/arch/m32r/kernel/traps.c b/arch/m32r/kernel/traps.c
> +index cb79fba79d43..b88a8dd14933 100644
> +--- a/arch/m32r/kernel/traps.c
> ++++ b/arch/m32r/kernel/traps.c
> +@@ -122,7 +122,6 @@ void abort(void)
> +       /* if that doesn't kill us, halt */
> +       panic("Oops failed to kill thread");
> + }
> +-EXPORT_SYMBOL(abort);
> + 
> + void __init trap_init(void)
> + {
> +diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
> +index 5f25b39f04d4..c4ac6043ebb0 100644
> +--- a/arch/unicore32/kernel/traps.c
> ++++ b/arch/unicore32/kernel/traps.c
> +@@ -298,7 +298,6 @@ void abort(void)
> +       /* if that doesn't kill us, halt */
> +       panic("Oops failed to kill thread");
> + }
> +-EXPORT_SYMBOL(abort);
> + 
> + void __init trap_init(void)
> + {
> +diff --git a/kernel/exit.c b/kernel/exit.c
> +index df0c91d5606c..995453d9fb55 100644
> +--- a/kernel/exit.c
> ++++ b/kernel/exit.c
> +@@ -1763,3 +1763,4 @@ __weak void abort(void)
> +       /* if that doesn't kill us, halt */
> +       panic("Oops failed to kill thread");
> + }
> ++EXPORT_SYMBOL(abort);
> +-- 
> +2.11.0
> +
> -- 
> 2.11.0