69dce456e2
[ Upstream commit 528a4ab45300fa6283556d9b48e26b45a8aa15c4 ] Since scs allocation is moved to vmalloc region, the shadow stack is protected by kasan_posion_vmalloc. However, the vfree_atomic operation needs to access its context for scs_free process and causes kasan error as the dump info below. This patch Adds kasan_unpoison_vmalloc() before vfree_atomic, which aligns to the prior flow as using kmem_cache. The vmalloc region will go back posioned in the following vumap() operations. ================================================================== BUG: KASAN: vmalloc-out-of-bounds in llist_add_batch+0x60/0xd4 Write of size 8 at addr ffff8000100b9000 by task kthreadd/2 CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.15.0-rc2-11681-g92477dd1faa6-dirty #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x43c show_stack+0x1c/0x2c dump_stack_lvl+0x68/0x84 print_address_description+0x80/0x394 kasan_report+0x180/0x1dc __asan_report_store8_noabort+0x48/0x58 llist_add_batch+0x60/0xd4 vfree_atomic+0x60/0xe0 scs_free+0x1dc/0x1fc scs_release+0xa4/0xd4 free_task+0x30/0xe4 __put_task_struct+0x1ec/0x2e0 delayed_put_task_struct+0x5c/0xa0 rcu_do_batch+0x62c/0x8a0 rcu_core+0x60c/0xc14 rcu_core_si+0x14/0x24 __do_softirq+0x19c/0x68c irq_exit+0x118/0x2dc handle_domain_irq+0xcc/0x134 gic_handle_irq+0x7c/0x1bc call_on_irq_stack+0x40/0x70 do_interrupt_handler+0x78/0x9c el1_interrupt+0x34/0x60 el1h_64_irq_handler+0x1c/0x2c el1h_64_irq+0x78/0x7c _raw_spin_unlock_irqrestore+0x40/0xcc sched_fork+0x4f0/0xb00 copy_process+0xacc/0x3648 kernel_clone+0x168/0x534 kernel_thread+0x13c/0x1b0 kthreadd+0x2bc/0x400 ret_from_fork+0x10/0x20 Memory state around the buggy address: ffff8000100b8f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff8000100b8f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffff8000100b9000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffff8000100b9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff8000100b9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== Suggested-by: Kuan-Ying Lee <kuan-ying.lee@mediatek.com> Acked-by: Will Deacon <will@kernel.org> Tested-by: Will Deacon <will@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Yee Lee <yee.lee@mediatek.com> Fixes: a2abe7cbd8fe ("scs: switch to vmapped shadow stacks") Link: https://lore.kernel.org/r/20210930081619.30091-1-yee.lee@mediatek.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.