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No description
9e36a204bd
When a local kptr is stashed in a map and freed when the map goes away,
currently an error like the below appears:
[ 39.195695] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u32:15/2875
[ 39.196549] caller is bpf_mem_free+0x56/0xc0
[ 39.196958] CPU: 15 PID: 2875 Comm: kworker/u32:15 Tainted: G O 6.2.0-13016-g22df776a9a86 #4477
[ 39.197897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[ 39.198949] Workqueue: events_unbound bpf_map_free_deferred
[ 39.199470] Call Trace:
[ 39.199703] <TASK>
[ 39.199911] dump_stack_lvl+0x60/0x70
[ 39.200267] check_preemption_disabled+0xbf/0xe0
[ 39.200704] bpf_mem_free+0x56/0xc0
[ 39.201032] ? bpf_obj_new_impl+0xa0/0xa0
[ 39.201430] bpf_obj_free_fields+0x1cd/0x200
[ 39.201838] array_map_free+0xad/0x220
[ 39.202193] ? finish_task_switch+0xe5/0x3c0
[ 39.202614] bpf_map_free_deferred+0xea/0x210
[ 39.203006] ? lockdep_hardirqs_on_prepare+0xe/0x220
[ 39.203460] process_one_work+0x64f/0xbe0
[ 39.203822] ? pwq_dec_nr_in_flight+0x110/0x110
[ 39.204264] ? do_raw_spin_lock+0x107/0x1c0
[ 39.204662] ? lockdep_hardirqs_on_prepare+0xe/0x220
[ 39.205107] worker_thread+0x74/0x7a0
[ 39.205451] ? process_one_work+0xbe0/0xbe0
[ 39.205818] kthread+0x171/0x1a0
[ 39.206111] ? kthread_complete_and_exit+0x20/0x20
[ 39.206552] ret_from_fork+0x1f/0x30
[ 39.206886] </TASK>
This happens because the call to __bpf_obj_drop_impl I added in the patch
adding support for stashing local kptrs doesn't disable migration. Prior
to that patch, __bpf_obj_drop_impl logic only ran when called by a BPF
progarm, whereas now it can be called from map free path, so it's
necessary to explicitly disable migration.
Also, refactor a bit to just call __bpf_obj_drop_impl directly instead
of bothering w/ dtor union and setting pointer-to-obj_drop.
Fixes:
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
.rustfmt.toml | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.