[Bug gdb/34569] New: Memory error when printing array with @ syntax and size over 20550 elements

https://sourceware.org/bugzilla/show_bug.cgi?id=34569

            Bug ID: 34569
           Summary: Memory error when printing array with @ syntax and
                    size over 20550 elements
           Product: gdb
           Version: 16.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: oivil.trash at gmail dot com
  Target Milestone: ---

When printing an array with more than 20550 elements with the @ operator gdb
crashes with 'fatal glibc error', the problem arises only using @.
Backtrace:

Fatal glibc error: malloc.c:2601 (sysmalloc): assertion failed: (old_top ==
initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE &&
prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)


Fatal signal: Annullato
----- Backtrace -----
0x559d45037139 ???
0x559d451681ae ???
0x7fd5aad5bdef ???
0x7fd5aadb095c ???
0x7fd5aad5bcc1 raise
0x7fd5aad444ab abort
0x7fd5aad45290 ???
0x7fd5aad543b0 ???
0x7fd5aadbd1d6 ???
0x7fd5aadbe1aa ???
0x7fd5aadbff86 calloc
0x559d44fcf494 ???
0x559d454694b9 ???
0x559d4546beaf ???
0x559d454575d9 ???
0x559d45161037 ???
0x559d452ad19c ???
0x559d452ad7ed ???
0x559d45077074 ???
0x559d454063cf ???
0x559d45168c8f ???
0x559d4516a883 ???
0x559d45169927 ???
0x7fd5abf6fa1c rl_callback_read_char
0x559d45169aad ???
0x559d45169c81 ???
0x559d4544acdc ???
0x559d4557f0f5 ???
0x559d4557fe55 ???
0x559d4524a0b9 ???
0x559d4524d2f4 ???
0x559d44f7e489 ???
0x7fd5aad45ca7 ???
0x7fd5aad45d64 __libc_start_main
0x559d44f8acb0 ???
0xffffffffffffffff ???
---------------------
A fatal error internal to GDB has been detected, further
debugging is not possible.  GDB will now terminate.

Environment:
OS: 6.12.101+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.101-1 (2026-08-05)
x86_64 GNU/Linux
GCC version: 14.2.0
GDB configuration: x86_64-linux-gnu

How to repeat:
Print an array of any type using the 'p *arr@n' syntax with n over 20550 to
trigger the bug.
Minimalist example:
compile 'int main(void) { int arr[size>20550]; }' with -O0, break on main and
print arr with the syntax specified above.

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