This fixes the following backtrace caused by hci_conn being freed
before le_read_features_complete but after
hci_le_read_remote_features_sync so hci_conn_del -> hci_cmd_sync_dequeue
is not able to prevent it:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
BUG: KASAN: slab-use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1688 [inline]
BUG: KASAN: slab-use-after-free in le_read_features_complete+0x5b/0x340 net/bluetooth/hci_sync.c:7344
Write of size 4 at addr ffff8880796b0010 by task kworker/u9:0/52
CPU: 0 UID: 0 PID: 52 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcd/0x630 mm/kasan/report.c:482
kasan_report+0xe0/0x110 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:194 [inline]
kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:200
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1688 [inline]
le_read_features_complete+0x5b/0x340 net/bluetooth/hci_sync.c:7344
hci_cmd_sync_work+0x1ff/0x430 net/bluetooth/hci_sync.c:334
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Allocated by task 5932:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
__hci_conn_add+0xf8/0x1c70 net/bluetooth/hci_conn.c:963
hci_conn_add_unset+0x76/0x100 net/bluetooth/hci_conn.c:1084
le_conn_complete_evt+0x639/0x1f20 net/bluetooth/hci_event.c:5714
hci_le_enh_conn_complete_evt+0x23d/0x380 net/bluetooth/hci_event.c:5861
hci_le_meta_evt+0x357/0x5e0 net/bluetooth/hci_event.c:7408
hci_event_func net/bluetooth/hci_event.c:7716 [inline]
hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7773
hci_rx_work+0x2c9/0xeb0 net/bluetooth/hci_core.c:4076
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Freed by task 5932:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
__kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6663 [inline]
kfree+0x2f8/0x6e0 mm/slub.c:6871
device_release+0xa4/0x240 drivers/base/core.c:2565
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1e7/0x590 lib/kobject.c:737
put_device drivers/base/core.c:3797 [inline]
device_unregister+0x2f/0xc0 drivers/base/core.c:3920
hci_conn_del_sysfs+0xb4/0x180 net/bluetooth/hci_sysfs.c:79
hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline]
hci_conn_del+0x657/0x1180 net/bluetooth/hci_conn.c:1234
hci_disconn_complete_evt+0x410/0xa00 net/bluetooth/hci_event.c:3451
hci_event_func net/bluetooth/hci_event.c:7719 [inline]
hci_event_packet+0xa10/0x11c0 net/bluetooth/hci_event.c:7773
hci_rx_work+0x2c9/0xeb0 net/bluetooth/hci_core.c:4076
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
The buggy address belongs to the object at ffff8880796b0000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 16 bytes inside of
freed 8192-byte region [ffff8880796b0000, ffff8880796b2000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x796b0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ff27280 0000000000000000 0000000000000001
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff27280 0000000000000000 0000000000000001
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001e5ac01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5657, tgid 5657 (dhcpcd-run-hook), ts 79819636908, free_ts 79814310558
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x25f/0x2440 mm/page_alloc.c:5183
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab mm/slub.c:3248 [inline]
new_slab+0x2c3/0x430 mm/slub.c:3302
___slab_alloc+0xe18/0x1c90 mm/slub.c:4651
__slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774
__slab_alloc_node mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:5246 [inline]
__kmalloc_cache_noprof+0x477/0x800 mm/slub.c:5766
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
tomoyo_init_log+0xc8a/0x2140 security/tomoyo/audit.c:264
tomoyo_supervisor+0x302/0x13b0 security/tomoyo/common.c:2198
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x191/0x200 security/tomoyo/environ.c:63
tomoyo_environ security/tomoyo/domain.c:672 [inline]
tomoyo_find_next_domain+0xec1/0x20b0 security/tomoyo/domain.c:888
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline]
tomoyo_bprm_check_security+0x12d/0x1d0 security/tomoyo/tomoyo.c:92
security_bprm_check+0x1b9/0x1e0 security/security.c:794
search_binary_handler fs/exec.c:1659 [inline]
exec_binprm fs/exec.c:1701 [inline]
bprm_execve fs/exec.c:1753 [inline]
bprm_execve+0x81e/0x1620 fs/exec.c:1729
do_execveat_common.isra.0+0x4a5/0x610 fs/exec.c:1859
page last free pid 5657 tgid 5657 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2901
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x130/0x170 mm/slub.c:3886
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4948 [inline]
slab_alloc_node mm/slub.c:5258 [inline]
__kmalloc_cache_noprof+0x274/0x800 mm/slub.c:5766
kmalloc_noprof include/linux/slab.h:957 [inline]
tomoyo_print_header security/tomoyo/audit.c:156 [inline]
tomoyo_init_log+0x197/0x2140 security/tomoyo/audit.c:255
tomoyo_supervisor+0x302/0x13b0 security/tomoyo/common.c:2198
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x191/0x200 security/tomoyo/environ.c:63
tomoyo_environ security/tomoyo/domain.c:672 [inline]
tomoyo_find_next_domain+0xec1/0x20b0 security/tomoyo/domain.c:888
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline]
tomoyo_bprm_check_security+0x12d/0x1d0 security/tomoyo/tomoyo.c:92
security_bprm_check+0x1b9/0x1e0 security/security.c:794
search_binary_handler fs/exec.c:1659 [inline]
exec_binprm fs/exec.c:1701 [inline]
bprm_execve fs/exec.c:1753 [inline]
bprm_execve+0x81e/0x1620 fs/exec.c:1729
do_execveat_common.isra.0+0x4a5/0x610 fs/exec.c:1859
do_execve fs/exec.c:1933 [inline]
__do_sys_execve fs/exec.c:2009 [inline]
__se_sys_execve fs/exec.c:2004 [inline]
__x64_sys_execve+0x8e/0xb0 fs/exec.c:2004
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
Memory state around the buggy address:
ffff8880796aff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880796aff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880796b0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880796b0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880796b0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst