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From: Daniel Borkmann <daniel@iogearbox.net>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>, davem@davemloft.net
Cc: andrii@kernel.org, tj@kernel.org, memxor@gmail.com,
	delyank@fb.com, linux-mm@kvack.org, bpf@vger.kernel.org,
	kernel-team@fb.com
Subject: Re: [PATCH v4 bpf-next 01/15] bpf: Introduce any context BPF specific memory allocator.
Date: Mon, 29 Aug 2022 23:30:52 +0200	[thread overview]
Message-ID: <74acd56b-21bb-8ea8-092f-d1b4fcfc0790@iogearbox.net> (raw)
In-Reply-To: <20220826024430.84565-2-alexei.starovoitov@gmail.com>

On 8/26/22 4:44 AM, Alexei Starovoitov wrote:
[...]
> +
> +/* Called from BPF program or from sys_bpf syscall.
> + * In both cases migration is disabled.
> + */
> +void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size)
> +{
> +	int idx;
> +	void *ret;
> +
> +	if (!size)
> +		return ZERO_SIZE_PTR;
> +
> +	idx = bpf_mem_cache_idx(size + LLIST_NODE_SZ);
> +	if (idx < 0)
> +		return NULL;
> +
> +	ret = unit_alloc(this_cpu_ptr(ma->caches)->cache + idx);
> +	return !ret ? NULL : ret + LLIST_NODE_SZ;
> +}
> +
> +void notrace bpf_mem_free(struct bpf_mem_alloc *ma, void *ptr)
> +{
> +	int idx;
> +
> +	if (!ptr)
> +		return;
> +
> +	idx = bpf_mem_cache_idx(__ksize(ptr - LLIST_NODE_SZ));
> +	if (idx < 0)
> +		return;
> +
> +	unit_free(this_cpu_ptr(ma->caches)->cache + idx, ptr);
> +}
> +
> +void notrace *bpf_mem_cache_alloc(struct bpf_mem_alloc *ma)
> +{
> +	void *ret;
> +
> +	ret = unit_alloc(this_cpu_ptr(ma->cache));
> +	return !ret ? NULL : ret + LLIST_NODE_SZ;
> +}
> +
> +void notrace bpf_mem_cache_free(struct bpf_mem_alloc *ma, void *ptr)
> +{
> +	if (!ptr)
> +		return;
> +
> +	unit_free(this_cpu_ptr(ma->cache), ptr);
> +}

Looks like smp_processor_id() needs to be made aware that preemption might
be ok just not migration to a different CPU?

   [...]
   [  593.639025] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:246/1946
   [  593.639026] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:83/1642
   [  593.639138] caller is bpf_mem_cache_free+0x14/0x40
   [  593.640971] caller is bpf_mem_cache_free+0x14/0x40
   [  593.641060] CPU: 6 PID: 1642 Comm: kworker/u16:83 Not tainted 5.19.0-gf0d7b67fb6f8 #1
   [  593.641874] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
   [  593.641874] Workqueue: events_unbound bpf_map_free_deferred
   [  593.641874] Call Trace:
   [  593.641874]  <TASK>
   [  593.641874]  dump_stack_lvl+0x69/0x9b
   [  593.641874]  check_preemption_disabled+0x10b/0x120
   [  593.641874]  bpf_mem_cache_free+0x14/0x40
   [  593.641874]  htab_map_free+0x13f/0x2a0
   [  593.641874]  process_one_work+0x28e/0x580
   [  593.641874]  worker_thread+0x1fb/0x420
   [  593.641874]  ? rcu_lock_release+0x20/0x20
   [  593.641874]  kthread+0xf1/0x110
   [  593.641874]  ? kthread_blkcg+0x40/0x40
   [  593.641874]  ret_from_fork+0x22/0x30
   [  593.641874]  </TASK>
   [  593.654117] CPU: 5 PID: 1946 Comm: kworker/u16:246 Not tainted 5.19.0-gf0d7b67fb6f8 #1
   [  593.654317] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:83/1642
   [  593.654560] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
   [  593.654560] Workqueue: events_unbound bpf_map_free_deferred
   [  593.654560] Call Trace:
   [  593.654560]  <TASK>
   [  593.654560]  dump_stack_lvl+0x69/0x9b
   [  593.658872] caller is bpf_mem_cache_free+0x14/0x40
   [  593.654560]  check_preemption_disabled+0x10b/0x120
   [  593.654560]  bpf_mem_cache_free+0x14/0x40
   [  593.654560]  htab_map_free+0x13f/0x2a0
   [  593.654560]  process_one_work+0x28e/0x580
   [  593.654560]  worker_thread+0x1fb/0x420
   [  593.654560]  ? rcu_lock_release+0x20/0x20
   [  593.654560]  kthread+0xf1/0x110
   [  593.654560]  ? kthread_blkcg+0x40/0x40
   [  593.654560]  ret_from_fork+0x22/0x30
   [  593.654560]  </TASK>
   [...]
   [ 1158.399989] test_maps invoked oom-killer: gfp_mask=0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), order=0, oom_score_adj=0
   [ 1158.401948] CPU: 1 PID: 4147 Comm: test_maps Not tainted 5.19.0-gf0d7b67fb6f8 #1
   [ 1158.402612] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
   [ 1158.402666] Call Trace:
   [ 1158.402666]  <TASK>
   [ 1158.402666]  dump_stack_lvl+0x69/0x9b
   [ 1158.402666]  dump_header+0x4d/0x370
   [ 1158.402666]  out_of_memory+0x5a2/0x5e0
   [ 1158.402666]  __alloc_pages_slowpath+0xbf4/0x1140
   [ 1158.402666]  __alloc_pages+0x222/0x2c0
   [ 1158.402666]  folio_alloc+0x14/0x40
   [ 1158.402666]  filemap_alloc_folio+0x43/0x150
   [ 1158.402666]  __filemap_get_folio+0x263/0x3a0
   [ 1158.402666]  filemap_fault+0x20f/0x540
   [ 1158.410527]  __do_fault+0x4a/0x100
   [ 1158.410527]  do_fault+0x13a/0x630
   [ 1158.410527]  handle_mm_fault+0x83d/0x13d0
   [ 1158.410527]  do_user_addr_fault+0x33c/0x4e0
   [ 1158.410527]  exc_page_fault+0x72/0x280
   [ 1158.410527]  asm_exc_page_fault+0x22/0x30
   [ 1158.410527] RIP: 0033:0x7fa4d11a6ffc
   [ 1158.410527] Code: Unable to access opcode bytes at RIP 0x7fa4d11a6fd2.
   [ 1158.410527] RSP: 002b:00007ffd4fa8ac00 EFLAGS: 00000206
   [ 1158.410527] RAX: 0000000000000240 RBX: 0000000000000075 RCX: 00007fa4d11d4610
   [ 1158.410527] RDX: 0000000000000065 RSI: 00007fa4d11d42a0 RDI: 000055d328f91ac8
   [ 1158.410527] RBP: 00007ffd4fa8ace0 R08: 00007fa4d1198aa0 R09: 0000000000000001
   [ 1158.419624] R10: 00007ffd4fa8ace0 R11: 0000000000000246 R12: 000055d328f91ac8
   [ 1158.420234] R13: 000055d328f9e4e0 R14: 0000000000000000 R15: 00007fa4d11d3000
   [ 1158.420234]  </TASK>
   [...]


  reply	other threads:[~2022-08-29 21:31 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-26  2:44 [PATCH v4 bpf-next 00/15] bpf: " Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 01/15] bpf: Introduce any context " Alexei Starovoitov
2022-08-29 21:30   ` Daniel Borkmann [this message]
2022-08-29 21:45     ` Alexei Starovoitov
2022-08-29 21:59   ` Daniel Borkmann
2022-08-29 22:04     ` Alexei Starovoitov
2022-08-29 22:39   ` Martin KaFai Lau
2022-08-29 22:42     ` Alexei Starovoitov
2022-08-29 22:59       ` Kumar Kartikeya Dwivedi
2022-08-29 23:13         ` Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 02/15] bpf: Convert hash map to bpf_mem_alloc Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 03/15] selftests/bpf: Improve test coverage of test_maps Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 04/15] samples/bpf: Reduce syscall overhead in map_perf_test Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 05/15] bpf: Relax the requirement to use preallocated hash maps in tracing progs Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 06/15] bpf: Optimize element count in non-preallocated hash map Alexei Starovoitov
2022-08-29 21:47   ` Daniel Borkmann
2022-08-29 21:57     ` Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 07/15] bpf: Optimize call_rcu " Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 08/15] bpf: Adjust low/high watermarks in bpf_mem_cache Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 09/15] bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 10/15] bpf: Add percpu allocation support to bpf_mem_alloc Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 11/15] bpf: Convert percpu hash map to per-cpu bpf_mem_alloc Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 12/15] bpf: Remove tracing program restriction on map types Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 13/15] bpf: Prepare bpf_mem_alloc to be used by sleepable bpf programs Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 14/15] bpf: Remove prealloc-only restriction for " Alexei Starovoitov
2022-08-26  2:44 ` [PATCH v4 bpf-next 15/15] bpf: Introduce sysctl kernel.bpf_force_dyn_alloc Alexei Starovoitov
     [not found]   ` <f0e3e3ab-99b7-4d87-4b5a-b71ca7724310@iogearbox.net>
2022-08-29 22:27     ` Alexei Starovoitov
2022-08-27 16:57 ` [PATCH v4 bpf-next 00/15] bpf: BPF specific memory allocator Andrii Nakryiko
2022-08-27 22:53   ` Kumar Kartikeya Dwivedi
2022-08-29 15:47     ` Alexei Starovoitov
2022-09-09 20:10       ` Andrii Nakryiko

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