• Vamshi K Sthambamkadi's avatar
    tracing: Fix memory leaks in trace_events_hist.c · 9da73974
    Vamshi K Sthambamkadi authored
    kmemleak report 1:
        [<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
        [<05a2c9ed>] create_field_var+0xcf/0x180
        [<528a2d68>] action_create+0xe2/0xc80
        [<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
        [<28ea5d3d>] trigger_process_regex+0x7b/0xc0
        [<3138e86f>] event_trigger_write+0x4d/0xb0
        [<ffd66c19>] __vfs_write+0x30/0x200
        [<4f424a0d>] vfs_write+0x96/0x1b0
        [<da59a290>] ksys_write+0x53/0xc0
        [<3717101a>] __ia32_sys_write+0x15/0x20
        [<c5f23497>] do_fast_syscall_32+0x70/0x250
        [<46e2629c>] entry_SYSENTER_32+0xaf/0x102
    
    This is because save_vars[] of struct hist_trigger_data are
    not destroyed
    
    kmemleak report 2:
        [<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
        [<6e5e97c5>] create_var+0x3c/0x110
        [<de82f1b9>] create_field_var+0xaf/0x180
        [<528a2d68>] action_create+0xe2/0xc80
        [<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
        [<28ea5d3d>] trigger_process_regex+0x7b/0xc0
        [<3138e86f>] event_trigger_write+0x4d/0xb0
        [<ffd66c19>] __vfs_write+0x30/0x200
        [<4f424a0d>] vfs_write+0x96/0x1b0
        [<da59a290>] ksys_write+0x53/0xc0
        [<3717101a>] __ia32_sys_write+0x15/0x20
        [<c5f23497>] do_fast_syscall_32+0x70/0x250
        [<46e2629c>] entry_SYSENTER_32+0xaf/0x102
    
    struct hist_field allocated through create_var() do not initialize
    "ref" field to 1. The code in __destroy_hist_field() does not destroy
    object if "ref" is initialized to zero, the condition
    if (--hist_field->ref > 1) always passes since unsigned int wraps.
    
    kmemleak report 3:
        [<f8666fcc>] __kmalloc_track_caller+0x139/0x2b0
        [<bb7f80a5>] kstrdup+0x27/0x50
        [<39d70006>] init_var_ref+0x58/0xd0
        [<8ca76370>] create_var_ref+0x89/0xe0
        [<f045fc39>] action_create+0x38f/0xc80
        [<7c146821>] event_hist_trigger_func+0x15b5/0x1920
        [<07de3f61>] trigger_process_regex+0x7b/0xc0
        [<e87daf8f>] event_trigger_write+0x4d/0xb0
        [<19bf1512>] __vfs_write+0x30/0x200
        [<64ce4d27>] vfs_write+0x96/0x1b0
        [<a6f34170>] ksys_write+0x53/0xc0
        [<7d4230cd>] __ia32_sys_write+0x15/0x20
        [<8eadca00>] do_fast_syscall_32+0x70/0x250
        [<235cf985>] entry_SYSENTER_32+0xaf/0x102
    
    hist_fields (system & event_name) are not freed
    
    Link: http://lkml.kernel.org/r/20200422061503.GA5151@cosmosSigned-off-by: default avatarVamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
    Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    9da73974
trace_events_hist.c 177 KB