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charset=utf-8 Content-Disposition: inline In-Reply-To: <20250217042108.185932-1-longman@redhat.com> X-Rspamd-Queue-Id: 09621180012 X-Stat-Signature: ang93xycduqhfzesita8e64y4u4qy3nb X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1739806992-287443 X-HE-Meta: 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 B47vEI90 0xDkChX0sWwVkPXANL+uIf16JU8ffOxy+LUx8IR8vvHCfzUP7oAY4vhbIWg/oKp9PK0IvWS5WYj4iulyrmO8CUirfgXrsBJ1TtpYsP9N45cbDMo8p2xjfjd7cUGKKvAeeXCRWIXCUYSxB8BL5o7lY2bJ7v503TVwBPDgeZr0YDpjujBI/037aqZSzKWxxK7qCPMN+Te5VdQs/rcUuNrvlHz2N2N0Xqrm8jztUGQtVCmJHjegXzEQfLzI2kleClvqQSCyVlzF/HuXE8+cyOAU1w6j7I/OjSbhxJxk43l2N7U6b5BbIFg/zq1NDyFkKnFHDdBpUR5CMwQqfiUKAZcO6GNyLAg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-02-16 23:21:08 [-0500], Waiman Long wrote: I would skip the first part. The backtrace is not really helpful here. > The following bug report appeared with a test run in a RT debug kernel. > > [ 3359.353842] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 > [ 3359.353848] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 140605, name: kunit_try_catch > [ 3359.353853] preempt_count: 1, expected: 0 > : > [ 3359.353933] Call trace: > : > [ 3359.353955] rt_spin_lock+0x70/0x140 > [ 3359.353959] find_vmap_area+0x84/0x168 > [ 3359.353963] find_vm_area+0x1c/0x50 > [ 3359.353966] print_address_description.constprop.0+0x2a0/0x320 > [ 3359.353972] print_report+0x108/0x1f8 > [ 3359.353976] kasan_report+0x90/0xc8 > [ 3359.353980] __asan_load1+0x60/0x70 > > Commit e30a0361b851 ("kasan: make report_lock a raw spinlock") > changes report_lock to a raw_spinlock_t to avoid a similar RT problem. s/to avoid.*//. This has nothing to do with the problem at hand. > The print_address_description() function is called with report_lock > acquired and interrupt disabled. However, the find_vm_area() function > still needs to acquire a spinlock_t which becomes a sleeping lock in > the RT kernel. IOW, we can't call find_vm_area() in a RT kernel and > changing report_lock to a raw_spinlock_t is not enough to completely > solve this RT kernel problem. This function is always invoked under the report_lock which is a raw_spinlock_t. The context under this lock is always atomic even on PREEMPT_RT. find_vm_area() acquires vmap_node::busy.lock which is a spinlock_t, becoming a sleeping lock on PREEMPT_RT and must not be acquired in atomic context. > Fix this bug report by skipping the find_vm_area() call in this case > and just print out the address as is. Please use PREEMPT_RT instead of RT. Don't invoke find_vm_area() on PREEMPT_RT and just print the address. Non-PREEMPT_RT builds remain unchanged. Add a DEFINE_WAIT_OVERRIDE_MAP() is to tell lockdep that this lock nesting allowed because the PREEMPT_RT part (which is invalid) has been taken care of. > For !RT kernel, follow the example set in commit 0cce06ba859a > ("debugobjects,locking: Annotate debug_object_fill_pool() wait type > violation") and use DEFINE_WAIT_OVERRIDE_MAP() to avoid a spinlock_t > inside raw_spinlock_t warning. > Fixes: e30a0361b851 ("kasan: make report_lock a raw spinlock") > Signed-off-by: Waiman Long Reviewed-by: Sebastian Andrzej Siewior > --- > mm/kasan/report.c | 43 ++++++++++++++++++++++++++++++------------- > 1 file changed, 30 insertions(+), 13 deletions(-) > > [v3] Rename helper to print_vmalloc_info_set_page. > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > index 3fe77a360f1c..7c8c2e173aa4 100644 > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -370,6 +370,34 @@ static inline bool init_task_stack_addr(const void *addr) > sizeof(init_thread_union.stack)); > } > > +/* > + * RT kernel cannot call find_vm_area() in atomic context. For !RT kernel, > + * prevent spinlock_t inside raw_spinlock_t warning by raising wait-type > + * to WAIT_SLEEP. > + */ Do we need this comment? I lacks context of why it is atomic. And we have it in the commit description. > +static inline void print_vmalloc_info_set_page(void *addr, struct page **ppage) > +{ > + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { > + static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP); > + struct vm_struct *va; > + > + lock_map_acquire_try(&vmalloc_map); > + va = find_vm_area(addr); > + if (va) { > + pr_err("The buggy address belongs to the virtual mapping at\n" > + " [%px, %px) created by:\n" > + " %pS\n", > + va->addr, va->addr + va->size, va->caller); > + pr_err("\n"); > + > + *ppage = vmalloc_to_page(addr); > + } > + lock_map_release(&vmalloc_map); > + return; > + } > + pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr); > +} > + > static void print_address_description(void *addr, u8 tag, > struct kasan_report_info *info) > { Sebastian