Allow miscdev::Registration to carry some context with it.
#162
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
alex
reviewed
Apr 1, 2021
|
|
||
| impl Drop for Registration { | ||
| impl<T: Sync> Drop for Registration<T> { |
There was a problem hiding this comment.
Does T need to be Send as well so it can be dropped from any thread?
There was a problem hiding this comment.
No because its ownership remains with its creator, so it can ensure that it's called from the same thread.
I'm making Registration Send (if T is as well) so that the creator can destroy it from any thread if it wants to.
alex
approved these changes
Apr 1, 2021
ojeda
pushed a commit
that referenced
this pull request
May 28, 2025
apply_to_pte_range() enters the lazy MMU mode and then invokes kasan_populate_vmalloc_pte() callback on each page table walk iteration. However, the callback can go into sleep when trying to allocate a single page, e.g. if an architecutre disables preemption on lazy MMU mode enter. On s390 if make arch_enter_lazy_mmu_mode() -> preempt_enable() and arch_leave_lazy_mmu_mode() -> preempt_disable(), such crash occurs: [ 0.663336] BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:321 [ 0.663348] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd [ 0.663358] preempt_count: 1, expected: 0 [ 0.663366] RCU nest depth: 0, expected: 0 [ 0.663375] no locks held by kthreadd/2. [ 0.663383] Preemption disabled at: [ 0.663386] [<0002f3284cbb4eda>] apply_to_pte_range+0xfa/0x4a0 [ 0.663405] CPU: 0 UID: 0 PID: 2 Comm: kthreadd Not tainted 6.15.0-rc5-gcc-kasan-00043-gd76bb1ebb558-dirty #162 PREEMPT [ 0.663408] Hardware name: IBM 3931 A01 701 (KVM/Linux) [ 0.663409] Call Trace: [ 0.663410] [<0002f3284c385f58>] dump_stack_lvl+0xe8/0x140 [ 0.663413] [<0002f3284c507b9e>] __might_resched+0x66e/0x700 [ 0.663415] [<0002f3284cc4f6c0>] __alloc_frozen_pages_noprof+0x370/0x4b0 [ 0.663419] [<0002f3284ccc73c0>] alloc_pages_mpol+0x1a0/0x4a0 [ 0.663421] [<0002f3284ccc8518>] alloc_frozen_pages_noprof+0x88/0xc0 [ 0.663424] [<0002f3284ccc8572>] alloc_pages_noprof+0x22/0x120 [ 0.663427] [<0002f3284cc341ac>] get_free_pages_noprof+0x2c/0xc0 [ 0.663429] [<0002f3284cceba70>] kasan_populate_vmalloc_pte+0x50/0x120 [ 0.663433] [<0002f3284cbb4ef8>] apply_to_pte_range+0x118/0x4a0 [ 0.663435] [<0002f3284cbc7c14>] apply_to_pmd_range+0x194/0x3e0 [ 0.663437] [<0002f3284cbc99be>] __apply_to_page_range+0x2fe/0x7a0 [ 0.663440] [<0002f3284cbc9e88>] apply_to_page_range+0x28/0x40 [ 0.663442] [<0002f3284ccebf12>] kasan_populate_vmalloc+0x82/0xa0 [ 0.663445] [<0002f3284cc1578c>] alloc_vmap_area+0x34c/0xc10 [ 0.663448] [<0002f3284cc1c2a6>] __get_vm_area_node+0x186/0x2a0 [ 0.663451] [<0002f3284cc1e696>] __vmalloc_node_range_noprof+0x116/0x310 [ 0.663454] [<0002f3284cc1d950>] __vmalloc_node_noprof+0xd0/0x110 [ 0.663457] [<0002f3284c454b88>] alloc_thread_stack_node+0xf8/0x330 [ 0.663460] [<0002f3284c458d56>] dup_task_struct+0x66/0x4d0 [ 0.663463] [<0002f3284c45be90>] copy_process+0x280/0x4b90 [ 0.663465] [<0002f3284c460940>] kernel_clone+0xd0/0x4b0 [ 0.663467] [<0002f3284c46115e>] kernel_thread+0xbe/0xe0 [ 0.663469] [<0002f3284c4e440e>] kthreadd+0x50e/0x7f0 [ 0.663472] [<0002f3284c38c04a>] __ret_from_fork+0x8a/0xf0 [ 0.663475] [<0002f3284ed57ff2>] ret_from_fork+0xa/0x38 Instead of allocating single pages per-PTE, bulk-allocate the shadow memory prior to applying kasan_populate_vmalloc_pte() callback on a page range. Link: https://lkml.kernel.org/r/c61d3560297c93ed044f0b1af085610353a06a58.1747316918.git.agordeev@linux.ibm.com Fixes: 3c5c3cf ("kasan: support backing vmalloc space with real shadow memory") Signed-off-by: Alexander Gordeev <[email protected]> Suggested-by: Andrey Ryabinin <[email protected]> Reviewed-by: Harry Yoo <[email protected]> Cc: Daniel Axtens <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This is based on #160