KMSAN: uninit-value in bsearch

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    1e76a3e5 kmsan: replace __GFP_NO_KMSAN_SHADOW with kmsan_i..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=130b16fd600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d
dashboard link: https://syzkaller.appspot.com/bug?extid=427ce10b72235583ef69
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+427ce10b72235583ef69@xxxxxxxxxxxxxxxxxxxxxxxxx

dvb-usb: bulk message failed: -22 (1/-30591)
=====================================================
BUG: KMSAN: uninit-value in ir_lookup_by_scancode  
drivers/media/rc/rc-main.c:494 [inline]
BUG: KMSAN: uninit-value in rc_g_keycode_from_table  
drivers/media/rc/rc-main.c:582 [inline]
BUG: KMSAN: uninit-value in rc_keydown+0x1a6/0x6f0  
drivers/media/rc/rc-main.c:816
CPU: 1 PID: 11436 Comm: kworker/1:2 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events dvb_usb_read_remote_control
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x13a/0x2b0 mm/kmsan/kmsan_report.c:108
 __msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:250
 bsearch+0x1dd/0x250 lib/bsearch.c:41
 ir_lookup_by_scancode drivers/media/rc/rc-main.c:494 [inline]
 rc_g_keycode_from_table drivers/media/rc/rc-main.c:582 [inline]
 rc_keydown+0x1a6/0x6f0 drivers/media/rc/rc-main.c:816
 cxusb_rc_query+0x2e1/0x360 drivers/media/usb/dvb-usb/cxusb.c:548
 dvb_usb_read_remote_control+0xf9/0x290  
drivers/media/usb/dvb-usb/dvb-usb-remote.c:261
 process_one_work+0x1572/0x1ef0 kernel/workqueue.c:2269
 worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:150 [inline]
 kmsan_internal_chain_origin+0xd2/0x170 mm/kmsan/kmsan.c:314
 __msan_chain_origin+0x6b/0xe0 mm/kmsan/kmsan_instr.c:184
 rc_g_keycode_from_table drivers/media/rc/rc-main.c:583 [inline]
 rc_keydown+0x2c4/0x6f0 drivers/media/rc/rc-main.c:816
 cxusb_rc_query+0x2e1/0x360 drivers/media/usb/dvb-usb/cxusb.c:548
 dvb_usb_read_remote_control+0xf9/0x290  
drivers/media/usb/dvb-usb/dvb-usb-remote.c:261
 process_one_work+0x1572/0x1ef0 kernel/workqueue.c:2269
 worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Local variable description: ----ircode@cxusb_rc_query
Variable was created at:
 cxusb_rc_query+0x4d/0x360 drivers/media/usb/dvb-usb/cxusb.c:543
 dvb_usb_read_remote_control+0xf9/0x290  
drivers/media/usb/dvb-usb/dvb-usb-remote.c:261
=====================================================


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