Hi, On 16/11/21 07:23, Jun Miao wrote: > 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 ab00db216c9c7). > 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: 84109ab58590 ("rcu: Record kvfree_call_rcu() call stack for KASAN") > Fixes: 26e760c9a7c8 ("rcu: kasan: record and print call_rcu() call stack") > Reported-by: Jianwei Hu <jianwei.hu@xxxxxxxxxxxxx> > Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> > Signed-off-by: Jun Miao <jun.miao@xxxxxxxxx> > --- I gave this a quick try on RT. No splats. Nice! Tested-by: Juri Lelli <juri.lelli@xxxxxxxxxx> Best, Juri
