[Bug 264549] HardenedBSD: panic: e1000/bridge: "sleep on wchan ... with sleeping prohibited"
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Date: Tue, 28 Nov 2023 10:33:57 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=264549 Zhenlei Huang <zlei@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mmacy@FreeBSD.org --- Comment #2 from Zhenlei Huang <zlei@FreeBSD.org> --- (In reply to mfbott from comment #0) > I've solved this issue by replacing "pause" with "DELAY" inside the e1000 driver > (see attachment). > This certainly works for me, but could point to a deeper problem within anything > bridge-related. (I couldn't reproduce this panic outside a bridge.) IIUC this is an issue that combines use _sleep() with epoch_enter_preempt(). bridge_linkstate() will enter net epoch and then calls bstp_linkstate() and eventually e1000_write_phy_reg_mdic() / pause() / _sleep(). As per EPOCH(9), EPOCH_PREEMPT The epoch will allow preemption during sections. Only non-sleepable locks may be acquired during a preemptible epoch. The functions epoch_enter_preempt(), epoch_exit_preempt(), and epoch_wait_preempt() must be used in place of epoch_enter(), epoch_exit(), and epoch_wait(), respectively. it is wrong to sleep within net epoch (allow preemption). > There's possibly a better solution in which we allow "pause" under some > circumstances (unlike my blanket replacement), but I haven't found one. There's also problem report by Jean-Sébastien in https://reviews.freebsd.org/D14984 which has the same cause. CC the author @Matt Macy -- You are receiving this mail because: You are the assignee for the bug.