Hi, Valdis Klētnieks Thank you for your generous help. My understanding of this matter is on a different level with your help. >>Jul 3 10:23:31 yx kernel: [ 1176.166058] watchdog: BUG: soft lockup - >>CPU#0 stuck for 22s! [rt_cansend:1837] >>Jul 3 10:23:31 yx kernel: [ 1176.166066] Modules linked in: >>...... >>Jul 3 10:23:31 yx kernel: [ 1176.166252] Call Trace: >>Jul 3 10:23:31 yx kernel: [ 1176.166261] _raw_spin_lock+0x20/0x30 >>Jul 3 10:23:31 yx kernel: [ 1176.166270] can_write+0x6c/0x2c0 [advcan] >> >You get into function can_write() in module advcan. >That tries to take a spinlock, while something else already has it. Can I draw the conclusion that continually acquiring the spinlock causes the soft lockup and the CPU has been stuck for 22s? Can I think in this way? Thank you for your attention to this matter. Best Regards. Valdis Klētnieks <valdis.kletnieks@xxxxxx> 于2020年7月4日周六 下午12:39写道： > > > Could you please give me some hint on how to investigate the cause deeply? > > Shortening the call trace to the relevant lines: > > > Jul 3 10:23:31 yx kernel: [ 1176.166252] Call Trace: > > Jul 3 10:23:31 yx kernel: [ 1176.166261] _raw_spin_lock+0x20/0x30 > > Jul 3 10:23:31 yx kernel: [ 1176.166270] can_write+0x6c/0x2c0 [advcan] > > Jul 3 10:23:31 yx kernel: [ 1176.166292] __vfs_write+0x3a/0x190 > > You get into function can_write() in module advcan. > > That tries to take a spinlock, while something else already has it. > > The spinlock call is (roughly) 15% of the way through the function can_write(). > > The 'modules linked in' list includes "advcan(OE)". > > The 'O' tells us it's an out-of-tree module, which means you need to talk to > whoever wrote the module and find out why it's hanging on a spin lock (most > likely something else is failing to release it). > > And that's about as far as we can hint, since we don't have the source for your > out-of-tree module. If the people who wrote it would clean it up and get it > into the base Linux tree, then we'd all have access to it and be able to help > in much greater detail. > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
