Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Tom Zanussi
authored
Commit 656fe2ba (tracing: Use hist trigger's var_ref array to destroy var_refs) centralized the destruction of all the var_refs in one place so that other code didn't have to do it. The track_data_destroy() added later ignored that and also destroyed the track_data var_ref, causing a double-free error flagged by KASAN. ================================================================== BUG: KASAN: use-after-free in destroy_hist_field+0x30/0x70 Read of size 8 at addr ffff888086df2210 by task bash/1694 CPU: 6 PID: 1694 Comm: bash Not tainted 5.1.0-rc1-test+ #15 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 Call Trace: dump_stack+0x71/0xa0 ? destroy_hist_field+0x30/0x70 print_address_description.cold.3+0x9/0x1fb ? destroy_hist_field+0x30/0x70 ? destroy_hist_field+0x30/0x70 kasan_report.cold.4+0x1a/0x33 ? __kasan_slab_free+0x100/0x150 ? destroy_hist_field+0x30/0x70 destroy_hist_field+0x30/0x70 track_data_destroy+0x55/0xe0 destroy_hist_data+0x1f0/0x350 hist_unreg_all+0x203/0x220 event_trigger_open+0xbb/0x130 do_dentry_open+0x296/0x700 ? stacktrace_count_trigger+0x30/0x30 ? generic_permission+0x56/0x200 ? __x64_sys_fchdir+0xd0/0xd0 ? inode_permission+0x55/0x200 ? security_inode_permission+0x18/0x60 path_openat+0x633/0x22b0 ? path_lookupat.isra.50+0x420/0x420 ? __kasan_kmalloc.constprop.12+0xc1/0xd0 ? kmem_cache_alloc+0xe5/0x260 ? getname_flags+0x6c/0x2a0 ? do_sys_open+0x149/0x2b0 ? do_syscall_64+0x73/0x1b0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ? _raw_write_lock_bh+0xe0/0xe0 ? __kernel_text_address+0xe/0x30 ? unwind_get_return_address+0x2f/0x50 ? __list_add_valid+0x2d/0x70 ? deactivate_slab.isra.62+0x1f4/0x5a0 ? getname_flags+0x6c/0x2a0 ? set_track+0x76/0x120 do_filp_open+0x11a/0x1a0 ? may_open_dev+0x50/0x50 ? _raw_spin_lock+0x7a/0xd0 ? _raw_write_lock_bh+0xe0/0xe0 ? __alloc_fd+0x10f/0x200 do_sys_open+0x1db/0x2b0 ? filp_open+0x50/0x50 do_syscall_64+0x73/0x1b0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fa7b24a4ca2 Code: 25 00 00 41 00 3d 00 00 41 00 74 4c 48 8d 05 85 7a 0d 00 8b 00 85 c0 75 6d 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 0f 87 a2 00 00 00 48 8b 4c 24 28 64 48 33 0c 25 RSP: 002b:00007fffbafb3af0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055d3648ade30 RCX: 00007fa7b24a4ca2 RDX: 0000000000000241 RSI: 000055d364a55240 RDI: 00000000ffffff9c RBP: 00007fffbafb3bf0 R08: 0000000000000020 R09: 0000000000000002 R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000003 R14: 0000000000000001 R15: 000055d364a55240 ================================================================== So remove the track_data_destroy() destroy_hist_field() call for that var_ref. Link: http://lkml.kernel.org/r/1deffec420f6a16d11dd8647318d34a66d1989a9.camel@linux.intel.com Fixes: 466f4528 ("tracing: Generalize hist trigger onmax and save action") Reported-by:Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by:
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