Commit 469290648005e13b819a19353032ca53dda4378f made e6000sw's implementation of miibus_(read|write)reg assume that the softc lock is held. I presume that is to avoid lock recursion in e6000sw_attach() -> e6000sw_attach_miibus() -> mii_attach() -> MIIBUS_READREG(). However, the lock assertion in e6000sw_readphy_locked() can fail: panic: Lock e6000sw not exclusively locked @ /usr/home/markj/src/freebsd/sys/dev/etherswitch/e6000sw/e6000sw.c:773 cpuid = 0 time = 1698599456 KDB: stack backtrace: db_trace_self() at db_trace_self db_trace_self_wrapper() at db_trace_self_wrapper+0x38 vpanic() at vpanic+0x1a0 panic() at panic+0x48 _sx_assert() at _sx_assert+0x100 e6000sw_readphy_locked() at e6000sw_readphy_locked+0x40 gentbi_probe() at gentbi_probe+0x7c device_probe_child() at device_probe_child+0x150 device_probe() at device_probe+0xa0 device_probe_and_attach() at device_probe_and_attach+0x38 bus_generic_attach() at bus_generic_attach+0x1c miibus_attach() at miibus_attach+0x88 device_attach() at device_attach+0x3fc device_probe_and_attach() at device_probe_and_attach+0x80 bus_generic_driver_added() at bus_generic_driver_added+0x90 devclass_driver_added() at devclass_driver_added+0x48 devclass_add_driver() at devclass_add_driver+0x148 module_register_init() at module_register_init+0xb4 linker_load_module() at linker_load_module+0xacc kern_kldload() at kern_kldload+0x190 sys_kldload() at sys_kldload+0x64 do_el0_sync() at do_el0_sync+0x59c handle_el0_sync() at handle_el0_sync+0x48 In particular, gentbi_probe() obviously didn't acquire the softc lock.
https://reviews.freebsd.org/D42466
A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=725962a9f4c050b21488edd58d317e87c76d6f66 commit 725962a9f4c050b21488edd58d317e87c76d6f66 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2023-11-06 19:57:56 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2023-11-06 19:57:56 +0000 e6000sw: Fix locking in miibus_{read,write}reg implementations Commit 469290648005e13b819a19353032ca53dda4378f made e6000sw's implementation of miibus_(read|write)reg assume that the softc lock is held. I presume that is to avoid lock recursion in e6000sw_attach() -> e6000sw_attach_miibus() -> mii_attach() -> MIIBUS_READREG(). However, the lock assertion in e6000sw_readphy_locked() can fail if a different driver uses the interface to probe registers. Work around the problem by providing implementations which lock the softc if it is not already locked. PR: 274795 Fixes: 469290648005 ("e6000sw: add readphy and writephy wrappers") Reviewed by: kp, imp MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D42466 sys/dev/etherswitch/e6000sw/e6000sw.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-)
A commit in branch stable/14 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=766cceba19fe05095d81994e930a489ad545d42b commit 766cceba19fe05095d81994e930a489ad545d42b Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2023-11-06 19:57:56 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2023-11-13 14:41:50 +0000 e6000sw: Fix locking in miibus_{read,write}reg implementations Commit 469290648005e13b819a19353032ca53dda4378f made e6000sw's implementation of miibus_(read|write)reg assume that the softc lock is held. I presume that is to avoid lock recursion in e6000sw_attach() -> e6000sw_attach_miibus() -> mii_attach() -> MIIBUS_READREG(). However, the lock assertion in e6000sw_readphy_locked() can fail if a different driver uses the interface to probe registers. Work around the problem by providing implementations which lock the softc if it is not already locked. PR: 274795 Fixes: 469290648005 ("e6000sw: add readphy and writephy wrappers") Reviewed by: kp, imp MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D42466 (cherry picked from commit 725962a9f4c050b21488edd58d317e87c76d6f66) sys/dev/etherswitch/e6000sw/e6000sw.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-)