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![Alexei Starovoitov](/assets/img/avatar_default.png)
on x86 system with net.core.bpf_jit_enable = 1 sudo tcpdump -i eth1 'tcp port 22' causes the warning: [ 56.766097] Possible unsafe locking scenario: [ 56.766097] [ 56.780146] CPU0 [ 56.786807] ---- [ 56.793188] lock(&(&vb->lock)->rlock); [ 56.799593] <Interrupt> [ 56.805889] lock(&(&vb->lock)->rlock); [ 56.812266] [ 56.812266] *** DEADLOCK *** [ 56.812266] [ 56.830670] 1 lock held by ksoftirqd/1/13: [ 56.836838] #0: (rcu_read_lock){.+.+..}, at: [<ffffffff8118f44c>] vm_unmap_aliases+0x8c/0x380 [ 56.849757] [ 56.849757] stack backtrace: [ 56.862194] CPU: 1 PID: 13 Comm: ksoftirqd/1 Not tainted 3.12.0-rc3+ #45 [ 56.868721] Hardware name: System manufacturer System Product Name/P8Z77 WS, BIOS 3007 07/26/2012 [ 56.882004] ffffffff821944c0 ffff88080bbdb8c8 ffffffff8175a145 0000000000000007 [ 56.895630] ffff88080bbd5f40 ffff88080bbdb928 ffffffff81755b14 0000000000000001 [ 56.909313] ffff880800000001 ffff880800000000 ffffffff8101178f 0000000000000001 [ 56.923006] Call Trace: [ 56.929532] [<ffffffff8175a145>] dump_stack+0x55/0x76 [ 56.936067] [<ffffffff81755b14>] print_usage_bug+0x1f7/0x208 [ 56.942445] [<ffffffff8101178f>] ? save_stack_trace+0x2f/0x50 [ 56.948932] [<ffffffff810cc0a0>] ? check_usage_backwards+0x150/0x150 [ 56.955470] [<ffffffff810ccb52>] mark_lock+0x282/0x2c0 [ 56.961945] [<ffffffff810ccfed>] __lock_acquire+0x45d/0x1d50 [ 56.968474] [<ffffffff810cce6e>] ? __lock_acquire+0x2de/0x1d50 [ 56.975140] [<ffffffff81393bf5>] ? cpumask_next_and+0x55/0x90 [ 56.981942] [<ffffffff810cef72>] lock_acquire+0x92/0x1d0 [ 56.988745] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380 [ 56.995619] [<ffffffff817628f1>] _raw_spin_lock+0x41/0x50 [ 57.002493] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380 [ 57.009447] [<ffffffff8118f52a>] vm_unmap_aliases+0x16a/0x380 [ 57.016477] [<ffffffff8118f44c>] ? vm_unmap_aliases+0x8c/0x380 [ 57.023607] [<ffffffff810436b0>] change_page_attr_set_clr+0xc0/0x460 [ 57.030818] [<ffffffff810cfb8d>] ? trace_hardirqs_on+0xd/0x10 [ 57.037896] [<ffffffff811a8330>] ? kmem_cache_free+0xb0/0x2b0 [ 57.044789] [<ffffffff811b59c3>] ? free_object_rcu+0x93/0xa0 [ 57.051720] [<ffffffff81043d9f>] set_memory_rw+0x2f/0x40 [ 57.058727] [<ffffffff8104e17c>] bpf_jit_free+0x2c/0x40 [ 57.065577] [<ffffffff81642cba>] sk_filter_release_rcu+0x1a/0x30 [ 57.072338] [<ffffffff811108e2>] rcu_process_callbacks+0x202/0x7c0 [ 57.078962] [<ffffffff81057f17>] __do_softirq+0xf7/0x3f0 [ 57.085373] [<ffffffff81058245>] run_ksoftirqd+0x35/0x70 cannot reuse jited filter memory, since it's readonly, so use original bpf insns memory to hold work_struct defer kfree of sk_filter until jit completed freeing tested on x86_64 and i386 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
154 lines
3.5 KiB
C
154 lines
3.5 KiB
C
/*
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* Linux Socket Filter Data Structures
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*/
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#ifndef __LINUX_FILTER_H__
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#define __LINUX_FILTER_H__
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#include <linux/atomic.h>
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#include <linux/compat.h>
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#include <linux/workqueue.h>
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#include <uapi/linux/filter.h>
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#ifdef CONFIG_COMPAT
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/*
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* A struct sock_filter is architecture independent.
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*/
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struct compat_sock_fprog {
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u16 len;
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compat_uptr_t filter; /* struct sock_filter * */
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};
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#endif
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struct sk_buff;
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struct sock;
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struct sk_filter
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{
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atomic_t refcnt;
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unsigned int len; /* Number of filter blocks */
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struct rcu_head rcu;
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unsigned int (*bpf_func)(const struct sk_buff *skb,
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const struct sock_filter *filter);
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union {
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struct sock_filter insns[0];
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struct work_struct work;
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};
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};
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static inline unsigned int sk_filter_size(unsigned int proglen)
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{
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return max(sizeof(struct sk_filter),
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offsetof(struct sk_filter, insns[proglen]));
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}
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extern int sk_filter(struct sock *sk, struct sk_buff *skb);
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extern unsigned int sk_run_filter(const struct sk_buff *skb,
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const struct sock_filter *filter);
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extern int sk_unattached_filter_create(struct sk_filter **pfp,
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struct sock_fprog *fprog);
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extern void sk_unattached_filter_destroy(struct sk_filter *fp);
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extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
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extern int sk_detach_filter(struct sock *sk);
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extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
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extern int sk_get_filter(struct sock *sk, struct sock_filter __user *filter, unsigned len);
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extern void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to);
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#ifdef CONFIG_BPF_JIT
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#include <stdarg.h>
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#include <linux/linkage.h>
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#include <linux/printk.h>
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extern void bpf_jit_compile(struct sk_filter *fp);
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extern void bpf_jit_free(struct sk_filter *fp);
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static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
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u32 pass, void *image)
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{
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pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
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flen, proglen, pass, image);
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if (image)
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print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
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16, 1, image, proglen, false);
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}
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#define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
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#else
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#include <linux/slab.h>
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static inline void bpf_jit_compile(struct sk_filter *fp)
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{
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}
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static inline void bpf_jit_free(struct sk_filter *fp)
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{
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kfree(fp);
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}
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#define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
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#endif
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enum {
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BPF_S_RET_K = 1,
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BPF_S_RET_A,
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BPF_S_ALU_ADD_K,
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BPF_S_ALU_ADD_X,
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BPF_S_ALU_SUB_K,
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BPF_S_ALU_SUB_X,
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BPF_S_ALU_MUL_K,
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BPF_S_ALU_MUL_X,
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BPF_S_ALU_DIV_X,
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BPF_S_ALU_MOD_K,
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BPF_S_ALU_MOD_X,
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BPF_S_ALU_AND_K,
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BPF_S_ALU_AND_X,
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BPF_S_ALU_OR_K,
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BPF_S_ALU_OR_X,
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BPF_S_ALU_XOR_K,
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BPF_S_ALU_XOR_X,
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BPF_S_ALU_LSH_K,
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BPF_S_ALU_LSH_X,
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BPF_S_ALU_RSH_K,
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BPF_S_ALU_RSH_X,
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BPF_S_ALU_NEG,
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BPF_S_LD_W_ABS,
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BPF_S_LD_H_ABS,
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BPF_S_LD_B_ABS,
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BPF_S_LD_W_LEN,
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BPF_S_LD_W_IND,
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BPF_S_LD_H_IND,
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BPF_S_LD_B_IND,
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BPF_S_LD_IMM,
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BPF_S_LDX_W_LEN,
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BPF_S_LDX_B_MSH,
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BPF_S_LDX_IMM,
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BPF_S_MISC_TAX,
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BPF_S_MISC_TXA,
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BPF_S_ALU_DIV_K,
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BPF_S_LD_MEM,
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BPF_S_LDX_MEM,
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BPF_S_ST,
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BPF_S_STX,
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BPF_S_JMP_JA,
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BPF_S_JMP_JEQ_K,
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BPF_S_JMP_JEQ_X,
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BPF_S_JMP_JGE_K,
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BPF_S_JMP_JGE_X,
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BPF_S_JMP_JGT_K,
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BPF_S_JMP_JGT_X,
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BPF_S_JMP_JSET_K,
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BPF_S_JMP_JSET_X,
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/* Ancillary data */
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BPF_S_ANC_PROTOCOL,
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BPF_S_ANC_PKTTYPE,
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BPF_S_ANC_IFINDEX,
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BPF_S_ANC_NLATTR,
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BPF_S_ANC_NLATTR_NEST,
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BPF_S_ANC_MARK,
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BPF_S_ANC_QUEUE,
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BPF_S_ANC_HATYPE,
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BPF_S_ANC_RXHASH,
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BPF_S_ANC_CPU,
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BPF_S_ANC_ALU_XOR_X,
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BPF_S_ANC_SECCOMP_LD_W,
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BPF_S_ANC_VLAN_TAG,
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BPF_S_ANC_VLAN_TAG_PRESENT,
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BPF_S_ANC_PAY_OFFSET,
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};
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#endif /* __LINUX_FILTER_H__ */
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