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CPU numbers in reports are presumably wrong #201

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dvyukov opened this issue Sep 9, 2015 · 0 comments
Open

CPU numbers in reports are presumably wrong #201

dvyukov opened this issue Sep 9, 2015 · 0 comments
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bug KTSAN KTSAN-related issues wontfix

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@dvyukov
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dvyukov commented Sep 9, 2015

According to code these memory accesses seem to always happen on the same CPU, while in reports CPUs are always different:

ThreadSanitizer: data-race in tcp_wfree

Write of size 8 by thread T12 (K0, CPU3):
 [<     inlined    >] __list_add include/linux/list.h:43
 [<     inlined    >] list_add include/linux/list.h:63
 [<ffffffff81c4ab60>] tcp_wfree+0x130/0x1a0 net/ipv4/tcp_output.c:891
 [<ffffffff81b6b9e4>] skb_release_head_state+0x94/0x120 net/core/skbuff.c:644 (discriminator 3)
 [<ffffffff81b6d25d>] skb_release_all+0x1d/0x50 net/core/skbuff.c:657
 [<     inlined    >] __kfree_skb net/core/skbuff.c:673
 [<ffffffff81b6d510>] consume_skb+0x60/0x110 net/core/skbuff.c:746
 [<ffffffff81b8cddd>] __dev_kfree_skb_any+0x4d/0x60 net/core/dev.c:2312
 [<     inlined    >] dev_kfree_skb_any include/linux/netdevice.h:2933
 [<ffffffff8194ca33>] e1000_unmap_and_free_tx_resource.isra.42+0xd3/0x120 drivers/net/ethernet/intel/e1000/e1000_main.c:1973
 [<     inlined    >] e1000_clean_tx_irq drivers/net/ethernet/intel/e1000/e1000_main.c:3881
 [<ffffffff8194cccd>] e1000_clean+0x24d/0x11e0 drivers/net/ethernet/intel/e1000/e1000_main.c:3818
 [<     inlined    >] napi_poll net/core/dev.c:4744
 [<ffffffff81b90789>] net_rx_action+0x489/0x690 net/core/dev.c:4809
 [<ffffffff81091d7e>] __do_softirq+0xbe/0x300 kernel/softirq.c:273
 [<ffffffff81ee9e2b>] ret_from_intr+0x0/0x1f arch/x86/entry/entry_64.S:601
 [<ffffffff810166af>] arch_cpu_idle+0x1f/0x30 arch/x86/kernel/process.c:292
 [<ffffffff810dd48f>] default_idle_call+0x3f/0x60 kernel/sched/idle.c:89

Previous write of size 8 by thread T7 (K7, CPU2):
 [<     inlined    >] __list_splice include/linux/list.h:306
 [<     inlined    >] list_splice_init include/linux/list.h:345
 [<ffffffff81c50c21>] tcp_tasklet_func+0xb1/0x260 net/ipv4/tcp_output.c:767
 [<ffffffff81091561>] tasklet_action+0xc1/0x1f0 kernel/softirq.c:505
 [<ffffffff81eea11b>] apic_timer_interrupt+0x6b/0x70 arch/x86/entry/entry_64.S:782
 [<ffffffff810bbe20>] kthread+0x150/0x170 kernel/kthread.c:209
 [<ffffffff81ee96df>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:526

DBG: addr: ffff8804a0258dc8
DBG: first offset: 0, second offset: 0
DBG: T12 clock: {T12: 8804827, T7: 3091553}
DBG: T7 clock: {T7: 3091569}
@xairy xairy transferred this issue from google/ktsan Dec 23, 2021
@xairy xairy added bug KTSAN KTSAN-related issues labels Dec 23, 2021
@melver melver added the wontfix label Jan 25, 2022
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