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

Hauke Mehrtens hauke at hauke-m.de
Tue Jan 30 11:20:27 PST 2018 


On 01/30/2018 04:32 PM, Andrey Jr. Melnikov wrote:
> 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.

The patch already contain the full commit message and the hash so it is
pretty easy to find where they are from. I think this patch looks good.
I still hope that this will go into the 4.14 stable tree and we do not
have to maintain this any more.

Hauke

> 
>> ---
>>  .../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
> 
> 
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