Jun Miao 300c0c5e72 rcu: Avoid alloc_pages() when recording stack
The default kasan_record_aux_stack() calls stack_depot_save() with GFP_NOWAIT,
which in turn can then call alloc_pages(GFP_NOWAIT, ...).  In general, however,
it is not even possible to use either GFP_ATOMIC nor GFP_NOWAIT in certain
non-preemptive contexts/RT kernel including raw_spin_locks (see gfp.h and ab00db216c).
Fix it by instructing stackdepot to not expand stack storage via alloc_pages()
in case it runs out by using kasan_record_aux_stack_noalloc().

Jianwei Hu reported:
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:969
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 15319, name: python3
INFO: lockdep is turned off.
irq event stamp: 0
  hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  hardirqs last disabled at (0): [<ffffffff856c8b13>] copy_process+0xaf3/0x2590
  softirqs last  enabled at (0): [<ffffffff856c8b13>] copy_process+0xaf3/0x2590
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  CPU: 6 PID: 15319 Comm: python3 Tainted: G        W  O 5.15-rc7-preempt-rt #1
  Hardware name: Supermicro SYS-E300-9A-8C/A2SDi-8C-HLN4F, BIOS 1.1b 12/17/2018
  Call Trace:
    show_stack+0x52/0x58
    dump_stack+0xa1/0xd6
    ___might_sleep.cold+0x11c/0x12d
    rt_spin_lock+0x3f/0xc0
    rmqueue+0x100/0x1460
    rmqueue+0x100/0x1460
    mark_usage+0x1a0/0x1a0
    ftrace_graph_ret_addr+0x2a/0xb0
    rmqueue_pcplist.constprop.0+0x6a0/0x6a0
     __kasan_check_read+0x11/0x20
     __zone_watermark_ok+0x114/0x270
     get_page_from_freelist+0x148/0x630
     is_module_text_address+0x32/0xa0
     __alloc_pages_nodemask+0x2f6/0x790
     __alloc_pages_slowpath.constprop.0+0x12d0/0x12d0
     create_prof_cpu_mask+0x30/0x30
     alloc_pages_current+0xb1/0x150
     stack_depot_save+0x39f/0x490
     kasan_save_stack+0x42/0x50
     kasan_save_stack+0x23/0x50
     kasan_record_aux_stack+0xa9/0xc0
     __call_rcu+0xff/0x9c0
     call_rcu+0xe/0x10
     put_object+0x53/0x70
     __delete_object+0x7b/0x90
     kmemleak_free+0x46/0x70
     slab_free_freelist_hook+0xb4/0x160
     kfree+0xe5/0x420
     kfree_const+0x17/0x30
     kobject_cleanup+0xaa/0x230
     kobject_put+0x76/0x90
     netdev_queue_update_kobjects+0x17d/0x1f0
     ... ...
     ksys_write+0xd9/0x180
     __x64_sys_write+0x42/0x50
     do_syscall_64+0x38/0x50
     entry_SYSCALL_64_after_hwframe+0x44/0xa9

Links: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/kasan.h?id=7cb3007ce2da27ec02a1a3211941e7fe6875b642
Fixes: 84109ab585 ("rcu: Record kvfree_call_rcu() call stack for KASAN")
Fixes: 26e760c9a7 ("rcu: kasan: record and print call_rcu() call stack")
Reported-by: Jianwei Hu <jianwei.hu@windriver.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Marco Elver <elver@google.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Jun Miao <jun.miao@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-11-30 17:25:20 -08:00
2021-11-30 17:25:20 -08:00
2021-11-14 13:56:52 -08:00

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.
Description
No description provided
Readme 3.4 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%