On 2/12/25 5:21 PM, Waiman Long wrote:
> 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.
> 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.
>
> Fix this bug report by skipping the find_vm_area() call in this case
> and just print out the address as is.
>
> 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 <longman@xxxxxxxxxx>
> ---
> mm/kasan/report.c | 47 ++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 34 insertions(+), 13 deletions(-)
>
> [v2] Encapsulate the change into a new
> kasan_print_vmalloc_info_ret_page() helper
>
Not exactly what I had i mind, but this way is fine too.
Acked-by: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
