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| author | Vegard Nossum <vegard.nossum@oracle.com> | 2017-05-29 09:22:07 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-29 18:40:54 +0200 |
| commit | b0f5a8f32e8bbdaae1abb8abe2d3cbafaba57e08 (patch) | |
| tree | cfa80df40f7e628f2bd1380c6e679a83812c96b1 /arch | |
| parent | Linux 4.12-rc3 (diff) | |
| download | linux-b0f5a8f32e8bbdaae1abb8abe2d3cbafaba57e08.tar.xz linux-b0f5a8f32e8bbdaae1abb8abe2d3cbafaba57e08.zip | |
kthread: fix boot hang (regression) on MIPS/OpenRISC
This fixes a regression in commit 4d6501dce079 where I didn't notice
that MIPS and OpenRISC were reinitialising p->{set,clear}_child_tid to
NULL after our initialisation in copy_process().
We can simply get rid of the arch-specific initialisation here since it
is now always done in copy_process() before hitting copy_thread{,_tls}().
Review notes:
- As far as I can tell, copy_process() is the only user of
copy_thread_tls(), which is the only caller of copy_thread() for
architectures that don't implement copy_thread_tls().
- After this patch, there is no arch-specific code touching
p->set_child_tid or p->clear_child_tid whatsoever.
- It may look like MIPS/OpenRISC wanted to always have these fields be
NULL, but that's not true, as copy_process() would unconditionally
set them again _after_ calling copy_thread_tls() before commit
4d6501dce079.
Fixes: 4d6501dce079c1eb6bf0b1d8f528a5e81770109e ("kthread: Fix use-after-free if kthread fork fails")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net> # MIPS only
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/process.c | 1 | ||||
| -rw-r--r-- | arch/openrisc/kernel/process.c | 2 |
2 files changed, 0 insertions, 3 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 918d4c73e951..5351e1f3950d 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -120,7 +120,6 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, struct thread_info *ti = task_thread_info(p); struct pt_regs *childregs, *regs = current_pt_regs(); unsigned long childksp; - p->set_child_tid = p->clear_child_tid = NULL; childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c index f8da545854f9..106859ae27ff 100644 --- a/arch/openrisc/kernel/process.c +++ b/arch/openrisc/kernel/process.c @@ -167,8 +167,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp, top_of_kernel_stack = sp; - p->set_child_tid = p->clear_child_tid = NULL; - /* Locate userspace context on stack... */ sp -= STACK_FRAME_OVERHEAD; /* redzone */ sp -= sizeof(struct pt_regs); |