Messages in this thread | | | From | Seiji Aguchi <> | Date | Thu, 5 Jan 2012 12:35:43 -0500 | Subject | [RFC][PATCH v4 -next 0/4] Make pstore/kmsg_dump run after stopping other cpus in panic path |
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Hi,
Discussion: As Don mentioned in following thread, it would be nice for pstore/kmsg_dump to serialize panic path because they can log messages reliably.
https://lkml.org/lkml/2011/10/13/427
This patchset is based on his proposal switching smp_send_stop() from REBOOT_VECTOR to NMI.
Change Log:
v3 -> v4 - Add comment for explaining the purpose of WARN_ON() based on Don's comment (patch 2/4) https://lkml.org/lkml/2011/12/12/296
- Skip spin_lock of efi_pstore_write() in panic case based on discussion with Tony (patch 4/4) https://lkml.org/lkml/2012/1/3/151
- Apply this patchset to -next tree instead of linus -tree so that "patch 4/4" makes simple
v2 -> v3 - Skip spin_locks in panic case in both kmsg_dump() and pstore_dump() instead of calling spin_lock_init() to avoid potential issues due to spin_lock_init() - Add WARN_ON() in "in_nmi() and !panic" case into kmsg_dump() so that we trap when someone adds new kmsg_dump() in NMI path in the future - Skip subsequent kmsg_dump() function calls to avoid deadlock.
v1 -> v2 - Add trylocks to kmsg_dump()/pstore_dump() so that they can work in NMI context. - Divide a patch into two First one is just moving kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop() Second one is changing lock operations in kmsg_dump()/pstore_dump() v1 - Move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop - Bust logbuf_lock of kmsg_dump() in panic path for avoiding deadlock - Bust psinfo->buf_lock of pstore_dump() in panic path for avoiding deadlock
Patch Description: [RFC][PATCH v4 -next 1/4] Move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop() - Just move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop()
[RFC][PATCH v4 -next 2/4] Skip spin_locks in panic case and Add WARN_ON() - Skip spin_locks in panic case in both kmsg_dump() and pstore_dump() - Add WARN_ON() in "in_nmi() and !panic" case into kmsg_dump()
[RFC][PATCH v4 -next 3/4] Skip subsequent kmsg_dump() - Skip subsequent kmsg_dump() function calls in panic path
[RFC][PATCH v4 -next 4/4] Skip spin_lock of efi_pstore_write() in panic case - Skip spin_lock of efi_pstore_write() in panic case to avoid deadlock
Seiji
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