Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Free error logs of tracing instances When a tracing instance is removed, the error messages that hold errors that occurred in the instance needs to be freed. The following reports a memory leak: # cd /sys/kernel/tracing # mkdir instances/foo # echo 'hist:keys=x' > instances/foo/events/sched/sched_switch/trigger # cat instances/foo/error_log [ 117.404795] hist:sched:sched_switch: error: Couldn't find field Command: hist:keys=x ^ # rmdir instances/foo Then check for memory leaks: # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff88810d8ec700 (size 192): comm "bash", pid 869, jiffies 4294950577 (age 215.752s) hex dump (first 32 bytes): 60 dd 68 61 81 88 ff ff 60 dd 68 61 81 88 ff ff `.ha....`.ha.... a0 30 8c 83 ff ff ff ff 26 00 0a 00 00 00 00 00 .0......&....... backtrace: [] kmalloc_trace+0x2a/0xa0 [] tracing_log_err+0x277/0x2e0 [] parse_atom+0x966/0xb40 [] parse_expr+0x5f3/0xdb0 [] event_hist_trigger_parse+0x27f8/0x3560 [] trigger_process_regex+0x135/0x1a0 [] event_trigger_write+0x87/0xf0 [] vfs_write+0x162/0x670 [] ksys_write+0xca/0x170 [] do_syscall_64+0x3e/0xc0 [] entry_SYSCALL_64_after_hwframe+0x72/0xdc unreferenced object 0xffff888170c35a00 (size 32): comm "bash", pid 869, jiffies 4294950577 (age 215.752s) hex dump (first 32 bytes): 0a 20 20 43 6f 6d 6d 61 6e 64 3a 20 68 69 73 74 . Command: hist 3a 6b 65 79 73 3d 78 0a 00 00 00 00 00 00 00 00 :keys=x......... backtrace: [] __kmalloc+0x4d/0x160 [] tracing_log_err+0x29b/0x2e0 [] parse_atom+0x966/0xb40 [] parse_expr+0x5f3/0xdb0 [] event_hist_trigger_parse+0x27f8/0x3560 [] trigger_process_regex+0x135/0x1a0 [] event_trigger_write+0x87/0xf0 [] vfs_write+0x162/0x670 [] ksys_write+0xca/0x170 [] do_syscall_64+0x3e/0xc0 [] entry_SYSCALL_64_after_hwframe+0x72/0xdc The problem is that the error log needs to be freed when the instance is removed.