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feb18e900f
mvsas calls the non _gfp version of the libsas event notifiers API, leading
to the buggy call chains below:
mvsas/mv_sas.c: mvs_work_queue() [process context]
spin_lock_irqsave(mvs_info::lock, )
-> libsas/sas_event.c: sas_notify_phy_event()
-> sas_alloc_event()
-> in_interrupt() = false
-> invalid GFP_KERNEL allocation
-> libsas/sas_event.c: sas_notify_port_event()
-> sas_alloc_event()
-> in_interrupt() = false
-> invalid GFP_KERNEL allocation
Use the new event notifiers API instead, which requires callers to
explicitly pass the gfp_t memory allocation flags.
Below are context analysis for the modified functions:
=> mvs_bytes_dmaed():
Since it is invoked from both process and atomic contexts, let its callers
pass the gfp_t flags. Call chains:
scsi_scan.c: do_scsi_scan_host() [has msleep()]
-> shost->hostt->scan_start()
-> [mvsas/mv_init.c: Scsi_Host::scsi_host_template .scan_start = mvs_scan_start()]
-> mvsas/mv_sas.c: mvs_scan_start()
-> mvs_bytes_dmaed(..., GFP_KERNEL)
mvsas/mv_sas.c: mvs_work_queue()
spin_lock_irqsave(mvs_info::lock,)
-> mvs_bytes_dmaed(..., GFP_ATOMIC)
mvsas/mv_64xx.c: mvs_64xx_isr() || mvsas/mv_94xx.c: mvs_94xx_isr()
-> mvsas/mv_chips.h: mvs_int_full()
-> mvsas/mv_sas.c: mvs_int_port()
-> mvs_bytes_dmaed(..., GFP_ATOMIC);
=> mvs_work_queue():
Invoked from process context, but it calls all the libsas event notifier
APIs under a spin_lock_irqsave(). Pass GFP_ATOMIC.
Link: https://lore.kernel.org/r/20210118100955.1761652-5-a.darwish@linutronix.de
Fixes: 1c393b970e ("scsi: libsas: Use dynamic alloced work to avoid sas event lost")
Cc: Jason Yan <yanaijie@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.