kernel/trace/trace.c:2195 __ftrace_trace_stack() error: __builtin_memcpy() 'fstack->calls' too small (4096 vs u32max)

[kernel test robot <lkp@intel.com>]

Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Bill Wendling <morbo@google.com>
CC: Kees Cook <kees@kernel.org>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   36aad21d50d1af3f6954bb0c988257a908202477
commit: 2f70a9b7e9c74b92a85a2584090f0f5c4cbaa4be overflow: Match arithmetic in both parts of __builtin_choose_expr
date:   2 weeks ago
:::::: branch date: 5 hours ago
:::::: commit date: 2 weeks ago
config: um-randconfig-r2201-20261031 (https://download.01.org/0day-ci/archive/20261031/202610311050.WdhCzroo-lkp@intel.com/config)
compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)
smatch: v0.5.0-9187-g5189e3fb

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 2f70a9b7e9c7 ("overflow: Match arithmetic in both parts of __builtin_choose_expr")
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202610311050.WdhCzroo-lkp@intel.com/

smatch warnings:
kernel/trace/trace.c:2195 __ftrace_trace_stack() error: __builtin_memcpy() 'fstack->calls' too small (4096 vs u32max)
drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c:132 mlxsw_sp_counter_pool_init() error: __builtin_memcpy() 'mlxsw_sp_counter_sub_pools' too small (80 vs u32max)
lib/stackdepot.c:471 depot_alloc_stack() error: __builtin_memcpy() 'stack->entries' too small (256 vs u32max)

vim +2195 kernel/trace/trace.c

6ce5a6f0a07d37 Tatsuya S                2024-10-21  2186  
3e9a8aadca4807 Steven Rostedt (Red Hat  2016-11-23  2187) 	event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
e7186af7fb2609 Steven Rostedt (Google   2023-07-13  2188) 				    struct_size(entry, caller, nr_entries),
9deb193af69d3f Steven Rostedt (VMware   2021-04-01  2189) 				    trace_ctx);
3928a8a2d98081 Steven Rostedt           2008-09-29  2190  	if (!event)
4a9bd3f134decd Steven Rostedt           2011-07-14  2191  		goto out;
e7186af7fb2609 Steven Rostedt (Google   2023-07-13  2192) 	entry = ring_buffer_event_data(event);
86387f7ee5d327 Ingo Molnar              2008-05-12  2193  
ee6dd0db4d8de4 Thomas Gleixner          2019-04-25  2194  	entry->size = nr_entries;
e7186af7fb2609 Steven Rostedt (Google   2023-07-13 @2195) 	memcpy(&entry->caller, fstack->calls,
e7186af7fb2609 Steven Rostedt (Google   2023-07-13  2196) 	       flex_array_size(entry, caller, nr_entries));
4a9bd3f134decd Steven Rostedt           2011-07-14  2197  
7ffbd48d5cab22 Steven Rostedt           2012-10-11  2198  	__buffer_unlock_commit(buffer, event);
4a9bd3f134decd Steven Rostedt           2011-07-14  2199  
4a9bd3f134decd Steven Rostedt           2011-07-14  2200   out:
4a9bd3f134decd Steven Rostedt           2011-07-14  2201  	/* Again, don't let gcc optimize things here */
4a9bd3f134decd Steven Rostedt           2011-07-14  2202  	barrier();
821465295b3613 Shan Wei                 2012-11-19  2203  	__this_cpu_dec(ftrace_stack_reserve);
5f1ef0dfcb5b7f Steven Rostedt           2026-01-05  2204  	trace_clear_recursion(bit);
86387f7ee5d327 Ingo Molnar              2008-05-12  2205  }
86387f7ee5d327 Ingo Molnar              2008-05-12  2206  

:::::: The code at line 2195 was first introduced by commit
:::::: e7186af7fb2609584a8bfb3da3c6ae09da5a5224 tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure

:::::: TO: Steven Rostedt (Google) <rostedt@goodmis.org>
:::::: CC: Steven Rostedt (Google) <rostedt@goodmis.org>

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