# git rev-parse -q --verify a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025^{commit}
a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025
already have revision, skipping fetch
# git checkout -q -f -B kisskb a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025
# git clean -qxdf
# < git log -1
# commit a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025
# Author: Jason A. Donenfeld <Jason@zx2c4.com>
# Date:   Mon Sep 28 12:35:07 2020 +0200
# 
#     mm: do not rely on mm == current->mm in __get_user_pages_locked
#     
#     It seems likely this block was pasted from internal_get_user_pages_fast,
#     which is not passed an mm struct and therefore uses current's.  But
#     __get_user_pages_locked is passed an explicit mm, and current->mm is not
#     always valid. This was hit when being called from i915, which uses:
#     
#       pin_user_pages_remote->
#         __get_user_pages_remote->
#           __gup_longterm_locked->
#             __get_user_pages_locked
#     
#     Before, this would lead to an OOPS:
#     
#       BUG: kernel NULL pointer dereference, address: 0000000000000064
#       #PF: supervisor write access in kernel mode
#       #PF: error_code(0x0002) - not-present page
#       CPU: 10 PID: 1431 Comm: kworker/u33:1 Tainted: P S   U     O      5.9.0-rc7+ #140
#       Hardware name: LENOVO 20QTCTO1WW/20QTCTO1WW, BIOS N2OET47W (1.34 ) 08/06/2020
#       Workqueue: i915-userptr-acquire __i915_gem_userptr_get_pages_worker [i915]
#       RIP: 0010:__get_user_pages_remote+0xd7/0x310
#       Call Trace:
#        __i915_gem_userptr_get_pages_worker+0xc8/0x260 [i915]
#        process_one_work+0x1ca/0x390
#        worker_thread+0x48/0x3c0
#        kthread+0x114/0x130
#        ret_from_fork+0x1f/0x30
#       CR2: 0000000000000064
#     
#     This commit fixes the problem by using the mm pointer passed to the
#     function rather than the bogus one in current.
#     
#     Fixes: 008cfe4418b3 ("mm: Introduce mm_struct.has_pinned")
#     Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
#     Reported-by: Harald Arnesen <harald@skogtun.org>
#     Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
#     Reviewed-by: Peter Xu <peterx@redhat.com>
#     Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-ld --version
# < git log --format=%s --max-count=1 a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025
# < make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  se7619_defconfig
# < make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  help
# make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  olddefconfig
# make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
In file included from /kisskb/src/arch/sh/include/asm/hw_irq.h:6,
                 from /kisskb/src/include/linux/irq.h:576,
                 from /kisskb/src/arch/sh/include/asm/hardirq.h:6,
                 from /kisskb/src/include/linux/hardirq.h:10,
                 from /kisskb/src/include/linux/interrupt.h:11,
                 from /kisskb/src/include/linux/serial_core.h:13,
                 from /kisskb/src/include/linux/serial_sci.h:6,
                 from /kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:11:
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:105:24: note: in expansion of macro '_INTC_ARRAY'
  105 |  _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \
      |                        ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:106:2: note: in expansion of macro '_INTC_ARRAY'
  106 |  _INTC_ARRAY(mask_regs), _INTC_ARRAY(prio_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:2: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:27: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |                           ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/drivers/tty/serial/sh-sci.c: In function 'sci_remap_port':
/kisskb/src/drivers/tty/serial/sh-sci.c:2677:19: warning: unused variable 'sport' [-Wunused-variable]
 2677 |  struct sci_port *sport = to_sci_port(port);
      |                   ^~~~~
Completed OK
# rm -rf /kisskb/build/linus_se7619_defconfig_sh4-gcc10
# Build took: 0:00:34.781307