On 11/4/21 5:21 AM, Paul E. McKenney wrote:
[Please note: This e-mail is from an EXTERNAL e-mail address]
On Wed, Nov 03, 2021 at 11:13:15AM -0700, Paul E. McKenney wrote:
On Wed, Nov 03, 2021 at 02:55:48PM +0100, Uladzislau Rezki wrote:
On Wed, Nov 3, 2021 at 7:51 AM Jun Miao <jun.miao@xxxxxxxxxxxxx> wrote:
On 11/2/21 10:53 PM, Uladzislau Rezki wrote:
[Please note: This e-mail is from an EXTERNAL e-mail address]
Add KASAN maintainers
On 11/1/21 6:31 PM, 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
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>
Signed-off-by: Jun Miao <jun.miao@xxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8270e58cd0f3..2c1034580f15 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3026,7 +3026,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
head->func = func;
head->next = NULL;
local_irq_save(flags);
- kasan_record_aux_stack(head);
+ kasan_record_aux_stack_noalloc(head);
rdp = this_cpu_ptr(&rcu_data);
/* Add the callback to our list. */
@@ -3591,7 +3591,7 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
return;
}
- kasan_record_aux_stack(ptr);
+ kasan_record_aux_stack_noalloc(ptr);
success = add_ptr_to_bulk_krc_lock(&krcp, &flags, ptr, !head);
if (!success) {
run_page_cache_worker(krcp);
Yep an allocation is tricky here. This change looks correct to me at
least from the point that it does not allocate.
--
Uladzislau Rezki
Thanks your approval. Could you like to give me a review?
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
I have queued it for review and testing, thank you both! I do have
some remaining concerns about this code being starved for memory. I am
wondering if the code needs to check the interrupt state. And perhaps
also whether locks are held. I of course will refrain from sending
this to mainline until these concerns are resolved.
Marco, Dmitry, thoughts?
Well, the compiler does have an opinion:
kernel/rcu/tree.c: In function ‘__call_rcu’:
kernel/rcu/tree.c:3029:2: error: implicit declaration of function ‘kasan_record_aux_stack_noalloc’; did you mean ‘kasan_record_aux_stack’? [-Werror=implicit-function-declaration]
3029 | kasan_record_aux_stack_noalloc(head);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| kasan_record_aux_stack
I get the same message after merging in current mainline.
I have therefore dropped this patch for the time being.
Thanx, Paul
Hi Paul E,
The kasan_record_aux_stack_noalloc() is just introduce to linux-next
now, and marking "Notice: this object is not reachable from any branch."
in commit.
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/include/linux/kasan.h?h=next-20211029&id=2f64acf6b653d01fbdc92a693f12bbf71a205926
--- ---
Jun Miao
