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 ab00db21). 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: 84109ab5 ("rcu: Record kvfree_call_rcu() call stack for KASAN") Fixes: 26e760c9 ("rcu: kasan: record and print call_rcu() call stack") Reported-by:Jianwei Hu <jianwei.hu@windriver.com> Reviewed-by: