[SR-12079] libdispatch SEGFAULT when using Foundation's FileHandle readabilityHandler on lots of pipes

[weissi]

Previous ID	SR-12079
Radar	rdar://problem/58997211
Original Reporter	@weissi
Type	Bug

Attachment: Download

Additional Detail from JIRA

Votes	1
Component/s	Foundation
Labels	Bug, Crash
Assignee	None
Priority	Medium

md5: 507eb4e7b2c1f88b3f62677d14f5efd3

Issue Description:

The following program always opens 1000 Pipe s (sequentially), then sets up a readabilityHandler for each of the pipes, then closes the other end of the pipe, and waits for the readabilityHandlers to send an empty Data meaning EOF.

This works for a while until we get a SEGFAULT in dispatch here

(lldb) run
......................Process 24 stopped
* thread #​2, name = 'File', stop reason = signal SIGSEGV: invalid address (fault address: 0xffff800013ff70b7)
    frame #​0: 0x00007ffff60b516a libdispatch.so`_dispatch_event_loop_drain + 1242
libdispatch.so`_dispatch_event_loop_drain:
->  0x7ffff60b516a <+1242>: movl   0x8(%rcx), %edx
    0x7ffff60b516d <+1245>: cmpl   $0x7fffffff, %edx         ; imm = 0x7FFFFFFF
    0x7ffff60b5173 <+1251>: je     0x7ffff60b5187            ; <+1271>
    0x7ffff60b5175 <+1253>: movl   $0x2, %edx
Target 0: (File) stopped.

[...]

* thread #&#8203;2, name = 'File', stop reason = signal SIGSEGV: invalid address (fault address: 0xffff800013ff70b7)
  * frame #&#8203;0: 0x00007ffff60b516a libdispatch.so`_dispatch_event_loop_drain + 1242
    frame #&#8203;1: 0x00007ffff60a8ea2 libdispatch.so`_dispatch_mgr_invoke + 146
    frame #&#8203;2: 0x00007ffff60a8dee libdispatch.so`_dispatch_mgr_thread + 126
    frame #&#8203;3: 0x00007ffff60ac993 libdispatch.so`_dispatch_worker_thread + 515
    frame #&#8203;4: 0x00007ffff6a826db libpthread.so.0`start_thread + 219
    frame #&#8203;5: 0x00007ffff5ba388f libc.so.6`clone + 63

Please note that the fault address is 0xffff800013ff70b7 and given that the pointer value ends in 7 and we're looking at a 32 bit load, this looks like a nice memory corruption to because that's an unaligned 32 bit load which is unlikely to be how the code is meant to work.

Credit to rignatus (JIRA User) for finding the initial issue that led to us debugging this together.

Repro:

On Linux

swiftc -O File.swift && ./File

With lldb in Docker (runnable from macOS)

# assuming File is in .
docker run --privileged --rm -v "$PWD:$PWD" -w "$PWD" -it norionomura/swift:nightly  bash -c 'swiftc -O File.swift && lldb --batch -o run -k "image list" -k "register read" -k "bt all" -k "exit 134" ./File'

program reproduced here

import Foundation

for i in 1..<1_000_000 {
    fputs(".", stdout)
    fflush(stdout)
    if i % 100 == 0 {
        fputs("\n", stdout)
    }
    let g = DispatchGroup()
    let ps = (0..<1000).map { _ in Pipe() }
    ps.forEach { p in
        var numberOfCalls = 0
        g.enter()
        p.fileHandleForReading.readabilityHandler = { handle in
            if handle.availableData.isEmpty {
                numberOfCalls += 1
                precondition(numberOfCalls == 1)
                g.leave()
            }
        }
    }
    ps.forEach { p in
        try! p.fileHandleForWriting.close()
    }
    g.wait()
}

[weissi]

CC phabouzit (JIRA User)/@millenomi/@spevans

[weissi]

@swift-ci create

[weissi]

   docker run --privileged --rm -v "$PWD:$PWD" -w "$PWD" -it norionomura/swift:nightly  bash -c 'apt-get update && apt-get install strace && swiftc -O File.swift && strace -e trace=epoll_wait,epoll_ctl -ff ./File'

leads to which is interesting.

[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2994, NULL) = -1 ENOENT (No such file or directory)
[pid   239] epoll_ctl(2004, EPOLL_CTL_DEL, 2995, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2995, NULL) = -1 ENOENT (No such file or directory)
[pid   239] epoll_ctl(2004, EPOLL_CTL_DEL, 2996, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2996, NULL) = -1 ENOENT (No such file or directory)
[pid   236] epoll_wait(2004, [{EPOLLHUP, {u32=1677787328, u64=140567367450816}}, {EPOLLHUP, {u32=1677787392, u64=140567367450880}}, {EPOLLHUP, {u32=1677787456, u64=140567367450944}}, {EPOLLHUP, {u32=1677787520, u64=140567367451008}}, {EPOLLHUP, {u32=1677787584, u64=140567367451072}}, {EPOLLHUP, {u32=1677787648, u64=140567367451136}}, {EPOLLHUP, {u32=1677787712, u64=140567367451200}}, {EPOLLHUP, {u32=1677787776, u64=140567367451264}}], 16, -1) = 8
[pid   237] epoll_ctl(2004, EPOLL_CTL_DEL, 2997, NULL <unfinished ...>
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2997, NULL <unfinished ...>
[pid   237] <... epoll_ctl resumed> )   = 0
[pid   236] <... epoll_ctl resumed> )   = -1 ENOENT (No such file or directory)
[pid   238] epoll_ctl(2004, EPOLL_CTL_DEL, 2998, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2998, NULL) = -1 ENOENT (No such file or directory)
[pid   239] epoll_ctl(2004, EPOLL_CTL_DEL, 2999, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 2999, NULL) = -1 ENOENT (No such file or directory)
[pid   239] epoll_ctl(2004, EPOLL_CTL_DEL, 3000, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 3000, NULL) = -1 ENOENT (No such file or directory)
[pid   239] epoll_ctl(2004, EPOLL_CTL_DEL, 3001, NULL) = 0
[pid   236] epoll_ctl(2004, EPOLL_CTL_DEL, 3001, NULL) = -1 ENOENT (No such file or directory)

[beccadax]

@swift-ci create

[weissi]

@swift-ci create

[weissi]

still happening on main

$ jw-docker-swift-main bash -c 'swiftc -O test.swift && lldb --batch -o run -k "image list" -k "register read" -k "bt all" -k "exit 134" ./test'
docker.io/swiftlang/swift:nightly-main-bionic
(lldb) target create "./test"
Current executable set to '/tmp/test' (x86_64).
(lldb) run
.............Process 25 stopped
* thread #​2, name = 'test', stop reason = signal SIGSEGV: invalid address (fault address: 0xffff800013fe1a17)
    frame #​0: 0x00007ffff649e53a libdispatch.so`_dispatch_event_loop_drain + 1130
libdispatch.so`_dispatch_event_loop_drain:
->  0x7ffff649e53a <+1130>: movl   0x8(%rcx), %edx
    0x7ffff649e53d <+1133>: cmpl   $0x7fffffff, %edx         ; imm = 0x7FFFFFFF 
    0x7ffff649e543 <+1139>: je     0x7ffff649e557            ; <+1159>
    0x7ffff649e545 <+1141>: movl   $0x2, %edx
Target 0: (test) stopped.

Process 25 launched: '/tmp/test' (x86_64)

[weissi]

Still not fixed in either 5.6 or main.

$ jw-docker-swift-5.6 bash -c 'swiftc -O test.swift && lldb --batch -o run -k "image list" -k "register read" -k "bt all" -k "exit 134" ./test'
Unable to find image 'swift:5.6-focal' locally
5.6-focal: Pulling from library/swift
8e5c1b329fe3: Pull complete 
f82f1f6ea714: Pull complete 
66034e6bd3e5: Pull complete 
68bf25c86869: Pull complete 
Digest: sha256:c3e9e80db696df7aec4daa6a942b756b86772294996ef3ecc932d05253fb7b04
Status: Downloaded newer image for swift:5.6-focal
(lldb) target create "./test"
Current executable set to '/tmp/test' (x86_64).
(lldb) run
....................................................................................................
....................................................................................................
..........................................................Process 45 stopped
* thread apple/swift#2, name = 'test', stop reason = signal SIGSEGV: invalid address (fault address: 0xffff80000fff5bb7)
    frame #0: 0x00007ffff6ebcd6a libdispatch.so`_dispatch_event_loop_drain + 1130
libdispatch.so`_dispatch_event_loop_drain:
->  0x7ffff6ebcd6a <+1130>: movl   0x8(%rcx), %edx
    0x7ffff6ebcd6d <+1133>: cmpl   $0x7fffffff, %edx         ; imm = 0x7FFFFFFF 
    0x7ffff6ebcd73 <+1139>: je     0x7ffff6ebcd87            ; <+1159>
    0x7ffff6ebcd75 <+1141>: movl   $0x2, %edx
Target 0: (test) stopped.
Process 45 launched: '/tmp/test' (x86_64)

---

$ jw-docker-swift-main bash -c 'swiftc -O test.swift && lldb --batch -o run -k "image list" -k "register read" -k "bt all" -k "exit 134" ./test'
docker.io/swiftlang/swift:nightly-main
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'lldb'
(lldb) target create "./test"
Current executable set to '/tmp/test' (x86_64).
(lldb) run
....................................................................................................
....................................................................................................
....................................................................................................
....................................................................................................
.........................................................................................Process 44 stopped
* thread apple/swift#2, name = 'test', stop reason = signal SIGSEGV: invalid address (fault address: 0xffff800013fe74f7)
    frame #0: 0x00007ffff62e7fca libdispatch.so`_dispatch_event_loop_drain + 1130
libdispatch.so`_dispatch_event_loop_drain:
->  0x7ffff62e7fca <+1130>: movl   0x8(%rcx), %edx
    0x7ffff62e7fcd <+1133>: cmpl   $0x7fffffff, %edx         ; imm = 0x7FFFFFFF 
    0x7ffff62e7fd3 <+1139>: je     0x7ffff62e7fe7            ; <+1159>
    0x7ffff62e7fd5 <+1141>: movl   $0x2, %edx
Target 0: (test) stopped.
Process 44 launched: '/tmp/test' (x86_64)

[weissi]

Foundation broke behaviour here, readabilityHandler doesn't seem to be called with the empty Data on EOF anymore on Linux, still the case on Darwin.

But here's an updated 2025 version of the same issue:

import Foundation
import Synchronization

nonisolated(unsafe) let gStdout = fdopen(STDOUT_FILENO, "w")!
let numberOfPipes = CommandLine.arguments.dropFirst().first.flatMap(Int.init) ?? 512
print("numberOfPipes", numberOfPipes)

for i in 1..<1_000_000 {
    let calls = Atomic(0)
    let g = DispatchGroup()
    let ps = (0..<numberOfPipes).map { _ in Pipe() }
    ps.forEach { p in
        g.enter()
        p.fileHandleForReading.readabilityHandler = { handle in
            let availableData = handle.availableData
            guard availableData.last == UInt8(ascii: "X") else { return }
            calls.add(1, ordering: .sequentiallyConsistent)
            // print(handle, availableData.count, availableData.last)
            g.leave()
        }
    }
    ps.forEach { p in
        let x = write(
            p.fileHandleForWriting.fileDescriptor,
            String(repeating: ".", count: 100) + "X",
            101
        )
        precondition(x == 101, "ignore this failure, this is the repro program being lazy")
    }
    ps.forEach { p in
        try! p.fileHandleForWriting.close()
    }
    fputs(".", gStdout)
    fflush(gStdout)
    if i % 100 == 0 {
        fputs("\n", gStdout)
    }

    while .timedOut == g.wait(timeout: .now() + 3) {
        print("still waiting, seen so far: \(calls.load(ordering: .sequentiallyConsistent))")
    }
}

Run this on 6.0

root@aa96fb5de936:/tmp# swiftc -swift-version 6 repro.swift && SWIFT_BACKTRACE=interactive=off ./repro
numberOfPipes 512
....................................................................................................
....................................................................................................
....................................................................................................
....................................................................................................
...............................................................^C
root@aa96fb5de936:/tmp# swiftc -swift-version 6 repro.swift && SWIFT_BACKTRACE=interactive=off ./repro 1024
numberOfPipes 1024
.....................................................................................
💣 Program crashed: Bad pointer dereference at 0xffff000083fe5647

Thread 0 "repro":

0  0x0000000000000000

Thread 1 crashed:

0      0x0000ffff8523d360 _dispatch_event_loop_drain + 1244 in libdispatch.so
1 [ra] 0x0000ffff85231e7c _dispatch_mgr_invoke + 123 in libdispatch.so
2 [ra] 0x0000ffff85231df0 _dispatch_mgr_thread + 131 in libdispatch.so
3 [ra] 0x0000ffff8523562c _dispatch_worker_thread + 431 in libdispatch.so
4 [ra] 0x0000ffff838c597c <unknown> in libc.so.6

Thread 2:

0  0x0000000000000000

Thread 3:

0  0x0000000000000000

Thread 4:

0  0x0000000000000000


Registers:

 x0 0x0000000000000001  1
 x1 0x0000000000000081  129
 x2 0x0000000000000001  1
 x3 0x0000000000000000  0
 x4 0x0000000000000000  0
 x5 0x0000000000000008  8
 x6 0x0000000000000000  0
 x7 0x0000000000000000  0
 x8 0xffff000083fe563f  18446462600947324479
 x9 0x0000000080000000  2147483648
x10 0x0000000000000000  0
x11 0x0000004000000000  274877906944
x12 0x0000000000000000  0
x13 0x0000000000000000  0
x14 0x00000000003ea67e  4105854
x15 0x0000000000000001  1
x16 0x0000000000000001  1
x17 0x0000ffff838cda70  fd 7b bd a9 fd 03 00 91 f3 53 01 a9 f4 03 00 aa  ý{½©ý···óS·©ô··ª
x18 0x0000000000000014  20
x19 0x0000ffff7c01a9c0  00 00 00 00 00 00 00 00 41 04 00 00 00 00 00 00  ········A·······
x20 0x0000000000000000  0
x21 0x0000ffff85272640  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
x22 0x000000000000000e  14
x23 0x0000000000000010  16
x24 0x0000ffff80c0e4e8  10 00 00 00 00 00 00 00 10 ad 01 7c ff ff 00 00  ·········­·|ÿÿ··
x25 0x0000ffff7c01a9d0  90 04 00 7c ff ff 00 00 90 04 00 7c ff ff 00 00  ···|ÿÿ·····|ÿÿ··
x26 0xffffffffffffffff  18446744073709551615
x27 0x000000007fffffff  2147483647
x28 0x0000ffff85272000  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
 fp 0x0000ffff80c0e670  10 e7 c0 80 ff ff 00 00 7c 1e 23 85 ff ff 00 00  ·çÀ·ÿÿ··|·#·ÿÿ··
 lr 0x0000ffff8523d344  f3 03 14 aa 34 fd ff b5 33 0f 40 f9 33 03 00 b4  ó··ª4ýÿµ3·@ù3··´
 sp 0x0000ffff80c0e4e0  00 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00  ················
 pc 0x0000ffff8523d360  09 09 40 b9 3f 01 1b 6b a0 00 00 54 01 21 00 91  ··@¹?··k ··T·!··


Images (18 omitted):

0x0000ffff83840000–0x0000ffff839d9c99 32fa4d6f3a8d5f430bdb7af2eb779470cd5ec7c2 libc.so.6      /usr/lib/aarch64-linux-gnu/libc.so.6
0x0000ffff85200000–0x0000ffff8524a1e4 <no build ID>                            libdispatch.so /usr/lib/swift/linux/libdispatch.so

Backtrace took 0.01s

Segmentation fault

on Darwin

$ swiftc -swift-version 6 repro.swift && echo GO && SWIFT_BACKTRACE=interactive=off ./repro
GO
numberOfPipes 512
......................................................still waiting, seen so far: 511
..............................................
....................................................................................................
......................still waiting, seen so far: 511
still waiting, seen so far: 511
..............................................................................
.........................................................................
[... keeps going ...]

[weissi]

Same with 6.1

$ jw-docker-swift-6.1  bash -c 'swiftc -swift-version 6 repro.swift && SWIFT_BACKTRACE=interactive=off ./repro 1024'
numberOfPipes 1024
...............................malloc_consolidate(): unaligned fastbin chunk detected

💣 Program crashed: Aborted at 0x0000000000000001

Thread 0 "repro":

0  0x0000000000000000

Thread 1:

0  0x0000000000000000

Thread 2 crashed:

 0              0x0000ffffba4d7608 <unknown> in libc.so.6
 1 [ra]         0x0000ffffba48cb3c <unknown> in libc.so.6
 2 [ra]         0x0000ffffba477e00 <unknown> in libc.so.6
 3 [ra]         0x0000ffffba4cabf4 <unknown> in libc.so.6
 4 [ra]         0x0000ffffba4e210c <unknown> in libc.so.6
 5 [ra]         0x0000ffffba4e2c38 <unknown> in libc.so.6
 6 [ra]         0x0000ffffba4e5278 <unknown> in libc.so.6
 7 [ra]         0x0000ffffba4e6660 <unknown> in libc.so.6
 8 [ra]         0x0000ffffbb023fb8 FileHandle._readDataOfLength(_:untilEOF:options:) + 331 in libFoundation.so
 9 [ra]         0x0000ffffbb023ce4 FileHandle.availableData.getter + 55 in libFoundation.so
10 [ra]         0x0000aaaabf1f3978 closure #1 in closure #4 in  + 79 in repro
11 [ra] [thunk] 0x0000ffffbb020410 partial apply for closure #1 in FileHandle.readabilityHandler.setter + 19 in libFoundation.so
12 [ra]         0x0000ffffbb0202c8 closure #1 in FileHandle.monitor(forReading:resumed:handler:) + 187 in libFoundation.so
13 [ra] [thunk] 0x0000ffffbb14b19c thunk for @escaping @callee_guaranteed () -> () + 27 in libFoundation.so
14 [ra]         0x0000ffffbb65ba7c _dispatch_continuation_pop + 267 in libdispatch.so
15 [ra]         0x0000ffffbb667c68 _dispatch_source_invoke + 1943 in libdispatch.so
16 [ra]         0x0000ffffbb65eee4 _dispatch_lane_serial_drain + 271 in libdispatch.so
17 [ra]         0x0000ffffbb65f82c _dispatch_lane_invoke + 255 in libdispatch.so
18 [ra]         0x0000ffffbb665118 _dispatch_worker_thread + 431 in libdispatch.so
19 [ra]         0x0000ffffba4d595c <unknown> in libc.so.6


Registers:

 x0 0x0000000000000000  0
 x1 0x00000000000000c1  193
 x2 0x0000000000000006  6
 x3 0x0000ffff16a0f0a0  01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
 x4 0x0000ffffbc0e3b50  00 82 77 96 b5 01 ef 53 00 00 00 00 00 00 00 00  ··w·µ·ïS········
 x5 0x0000000000000001  1
 x6 0x0000000000000020  32
 x7 0x0000000000000000  0
 x8 0x0000000000000083  131
 x9 0x0000000000000020  32
x10 0x000000000000000a  10
x11 0x0000ffff16a0e480  30 8d 05 fb aa aa 00 00 00 00 00 00 00 00 00 00  0··ûªª··········
x12 0x0000000000000009  9
x13 0x0000ffffbb620780  00 00 00 00 00 00 00 00 68 04 62 bb ff ff 00 00  ········h·b»ÿÿ··
x14 0x0000000000000000  0
x15 0x0000ffffbb6225b8  43 00 01 00 b0 e4 ff ff 90 fc ff ff 00 00 00 00  C···°äÿÿ·üÿÿ····
x16 0x0000000000000001  1
x17 0x0000ffffba4e65b0  fd 7b bc a9 fd 03 00 91 f7 63 03 a9 17 09 00 90  ý{¼©ý···÷c·©····
x18 0x0000000000000014  20
x19 0x00000000000000c1  193
x20 0x0000ffff16a0f0a0  01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
x21 0x0000000000000006  6
x22 0x0000ffff16a0e008  f0 e5 a0 16 ff ff 00 00 01 ef 5a ba ff ff 00 00  ðå ·ÿÿ···ïZºÿÿ··
x23 0x0000ffff16a0e008  f0 e5 a0 16 ff ff 00 00 01 ef 5a ba ff ff 00 00  ðå ·ÿÿ···ïZºÿÿ··
x24 0x0000ffff16a0e008  f0 e5 a0 16 ff ff 00 00 01 ef 5a ba ff ff 00 00  ðå ·ÿÿ···ïZºÿÿ··
x25 0x0000000000000037  55
x26 0x0000000000000000  0
x27 0x0000ffffb0000090  00 ea 01 b0 ff ff 00 00 b0 50 01 b0 ff ff 00 00  ·ê·°ÿÿ··°P·°ÿÿ··
x28 0x0000000000000bc0  3008
 fp 0x0000ffff16a0de90  d0 de a0 16 ff ff 00 00 3c cb 48 ba ff ff 00 00  ÐÞ ·ÿÿ··<ËHºÿÿ··
 lr 0x0000ffffba4d75f4  e1 03 13 aa e2 03 15 aa 00 7c 40 93 68 10 80 d2  á··ªâ··ª·|@·h··Ò
 sp 0x0000ffff16a0de80  00 00 00 00 00 00 00 00 00 82 77 96 b5 01 ef 53  ··········w·µ·ïS
 pc 0x0000ffffba4d7608  1f 04 40 31 e0 97 80 5a df ff ff 17 e0 03 16 aa  ··@1à··Zßÿÿ·à··ª


Images (16 omitted):

0x0000aaaabf1f0000–0x0000aaaabf1f54f8 06bc56c531e0d895a082ae192230f412083e7f9d repro            /tmp/repro
0x0000ffffba450000–0x0000ffffba5e9d89 1d7249a4f207d07166ff4be43acdc68a01faaa04 libc.so.6        /usr/lib/aarch64-linux-gnu/libc.so.6
0x0000ffffbae00000–0x0000ffffbb2c4c70 9049f7f071970504de7132ca29243c2b45cd0555 libFoundation.so /usr/lib/swift/linux/libFoundation.so
0x0000ffffbb630000–0x0000ffffbb67abb0 9d3be99ac1bfeac7bf6ad9c09ff973dd15567c4e libdispatch.so   /usr/lib/swift/linux/libdispatch.so

Backtrace took 0.04s

[weissi]

or

$ jw-docker-swift-6.1  bash -c 'swiftc -swift-version 6 repro.swift && SWIFT_BACKTRACE=interactive=off ./repro 1024'
numberOfPipes 1024
.........
💣 Program crashed: Bad pointer dereference at 0xffff000063fe4eb7

Thread 0 "repro":

0  0x0000000000000000

Thread 1 crashed:

0      0x0000ffffa6b6cdfc _dispatch_event_loop_drain + 1228 in libdispatch.so
1 [ra] 0x0000ffffa6b61e38 _dispatch_mgr_invoke + 123 in libdispatch.so
2 [ra] 0x0000ffffa6b61dac _dispatch_mgr_thread + 131 in libdispatch.so
3 [ra] 0x0000ffffa6b65118 _dispatch_worker_thread + 431 in libdispatch.so
4 [ra] 0x0000ffffa5ad595c <unknown> in libc.so.6

Thread 2:

0  0x0000000000000000

Thread 3:

0  0x0000000000000000


Registers:

 x0 0x0000000000000001  1
 x1 0x0000000000000081  129
 x2 0x0000000000000001  1
 x3 0x0000000000000000  0
 x4 0x0000000000000000  0
 x5 0x0000000000000008  8
 x6 0x0000000000000000  0
 x7 0x0000000000000000  0
 x8 0xffff000063fe4eaf  18446462600410451631
 x9 0x001ffe1c80000000  9005122638053376
x10 0x001ffe1c80000000  9005122638053376
x11 0x00007ff840000000  140704202358784
x12 0x0000000000000000  0
x13 0x0000000000000000  0
x14 0x00000000013711a0  20386208
x15 0x000000000000013e  318
x16 0x0000000000000001  1
x17 0x0000ffffa5adda50  fd 7b bd a9 fd 03 00 91 f3 53 01 a9 f4 03 00 aa  ý{½©ý···óS·©ô··ª
x18 0x0000000000000014  20
x19 0x00000000ffffffff  4294967295
x20 0x0000ffff9c01b150  00 00 00 00 00 00 00 00 41 12 00 00 00 00 00 00  ········A·······
x21 0x0000000000000000  0
x22 0x0000000000000000  0
x23 0x0000000000000010  16
x24 0x0000ffffa6ba2000  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
x25 0x0000ffff9c01b160  c0 06 00 9c ff ff 00 00 c0 06 00 9c ff ff 00 00  À···ÿÿ··À···ÿÿ··
x26 0x0000ffffa6ba2640  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ················
x27 0x0000000000000010  16
x28 0x000000007fffffff  2147483647
 fp 0x0000ffffa2e0e670  10 e7 e0 a2 ff ff 00 00 38 1e b6 a6 ff ff 00 00  ·çà¢ÿÿ··8·¶¦ÿÿ··
 lr 0x0000ffffa6b6cde0  f4 03 15 aa 15 fd ff b5 34 0f 40 f9 54 03 00 b4  ô··ª·ýÿµ4·@ùT··´
 sp 0x0000ffffa2e0e4e0  00 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00  ················
 pc 0x0000ffffa6b6cdfc  09 09 40 b9 3f 01 1c 6b a0 00 00 54 01 21 00 91  ··@¹?··k ··T·!··


Images (18 omitted):

0x0000ffffa5a50000–0x0000ffffa5be9d89 1d7249a4f207d07166ff4be43acdc68a01faaa04 libc.so.6      /usr/lib/aarch64-linux-gnu/libc.so.6
0x0000ffffa6b30000–0x0000ffffa6b7abb0 9d3be99ac1bfeac7bf6ad9c09ff973dd15567c4e libdispatch.so /usr/lib/swift/linux/libdispatch.so

Backtrace took 0.02s