ordinary user mode tasks.
In commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
The commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple enough
to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code sitting
in linux-next.
Link: https://lkml.kernel.org/r/87mtfu4up3.fsf@email.froward.int.ebiederm.org
Eric W. Biederman (8):
kthread: Don't allocate kthread_struct for init and umh
fork: Pass struct kernel_clone_args into copy_thread
fork: Explicity test for idle tasks in copy_thread
fork: Generalize PF_IO_WORKER handling
init: Deal with the init process being a user mode process
fork: Explicitly set PF_KTHREAD
fork: Stop allowing kthreads to call execve
sched: Update task_tick_numa to ignore tasks without an mm
arch/alpha/kernel/process.c | 13 ++++++------
arch/arc/kernel/process.c | 13 ++++++------
arch/arm/kernel/process.c | 12 ++++++-----
arch/arm64/kernel/process.c | 12 ++++++-----
arch/csky/kernel/process.c | 15 ++++++-------
arch/h8300/kernel/process.c | 10 ++++-----
arch/hexagon/kernel/process.c | 12 ++++++-----
arch/ia64/kernel/process.c | 15 +++++++------
arch/m68k/kernel/process.c | 12 ++++++-----
arch/microblaze/kernel/process.c | 12 ++++++-----
arch/mips/kernel/process.c | 13 ++++++------
arch/nios2/kernel/process.c | 12 ++++++-----
arch/openrisc/kernel/process.c | 12 ++++++-----
arch/parisc/kernel/process.c | 18 +++++++++-------
arch/powerpc/kernel/process.c | 15 +++++++------
arch/riscv/kernel/process.c | 12 ++++++-----
arch/s390/kernel/process.c | 12 ++++++-----
arch/sh/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_64.c | 12 ++++++-----
arch/um/kernel/process.c | 15 +++++++------
arch/x86/include/asm/fpu/sched.h | 2 +-
arch/x86/include/asm/switch_to.h | 8 +++----
arch/x86/kernel/fpu/core.c | 4 ++--
arch/x86/kernel/process.c | 18 +++++++++-------
arch/xtensa/kernel/process.c | 17 ++++++++-------
fs/exec.c | 8 ++++---
include/linux/sched/task.h | 8 +++++--
init/initramfs.c | 2 ++
init/main.c | 2 +-
kernel/fork.c | 46 +++++++++++++++++++++++++++++++++-------
kernel/sched/fair.c | 2 +-
kernel/umh.c | 6 +++---
33 files changed, 234 insertions(+), 160 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.
The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.
The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size". These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().
Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.
The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.
Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.
v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
$make versioncheck
arch/csky/include/asm/io.h: 8 linux/version.h not needed.
arch/csky/kernel/process.c: 5 linux/version.h not needed.
arch/csky/mm/dma-mapping.c: 12 linux/version.h not needed.
comments from Randy:
The patch makes sense but these are not compile warnings.
They come from scripts/checkversion.pl, which can be called
by 'make versioncheck', so I suppose that something in your
build system is running 'make versioncheck'.
Signed-off-by: Deyan Wang <wonder_rock@126.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign ->set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.
(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
These are used nowhere in the tree (except for some architectures which
define them for their own use) and were already removed for other
architectures in:
commit 6474924e2b ("arch: remove unused macro/function thread_saved_pc()")
commit c17c02040b ("arch: remove unused *_segments() macros/functions")
Remove them from arch/csky as well.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls()
back simply copy_thread(). It's a simpler name, and doesn't imply that only
tls is copied here. This finishes an outstanding chunk of internal process
creation work since we've added clone3().
Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>A
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>A
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The gdbmacros.txt use sp in thread_struct, but csky use ksp. This
cause bttnobp fail to excute.
TODO:
- Still couldn't display the contents of stack.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
The implementation of show_stack will panic with wrong fp:
addr = *fp++;
because the fp isn't checked properly.
The current implementations of show_stack, wchan and stack_trace
haven't been designed properly, so just deprecate them.
This patch is a reference to riscv's way, all codes are modified from
arm's. The patch is passed with:
- cat /proc/<pid>/stack
- cat /proc/<pid>/wchan
- echo c > /proc/sysrq-trigger
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
This is required for clone3 which passes the TLS value through a
struct rather than a register.
Cc: Amanieu d'Antras <amanieu@gmail.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
This is a basic -fstack-protector support without per-task canary
switching. The protector will report something like when stack
corruption is detected:
It's tested with strcpy local array overflow in sys_kill and get:
stack-protector: Kernel stack is corrupted in: sys_kill+0x23c/0x23c
TODO:
- Support task switch for different cannary
Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
We need set fp zero to let backtrace know the end. The patch fixup perf
callchain panic problem, because backtrace didn't know what is the end
of fp.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reported-by: Mao Han <han_mao@c-sky.com>
The gcc option "-mbacktrace" will push fp(r8),lr into stack and we could
unwind the stack with:
fp = *fp
lr = (unsigned int *)fp[1]
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
This patch adds files related to task_switch, sigcontext, signal,
fpu context switch.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Linus Torvalds