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As of v4.20, the swim3 driver crashes when loaded on a PowerBook G3 (Wallstreet). MacIO PCI driver attached to Gatwick chipset MacIO PCI driver attached to Heathrow chipset swim3 0.00015000:floppy: [fd0] SWIM3 floppy controller in media bay 0.00013020:ch-a: ttyS0 at MMIO 0xf3013020 (irq = 16, base_baud = 230400) is a Z85c30 ESCC - Serial port 0.00013000:ch-b: ttyS1 at MMIO 0xf3013000 (irq = 17, base_baud = 230400) is a Z85c30 ESCC - Infrared port macio: fixed media-bay irq on gatwick macio: fixed left floppy irqs swim3 1.00015000:floppy: [fd1] Couldn't request interrupt Unable to handle kernel paging request for data at address 0x00000024 Faulting instruction address: 0xc02652f8 Oops: Kernel access of bad area, sig: 11 [#1] BE SMP NR_CPUS=2 PowerMac Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.20.0 #2 NIP: c02652f8 LR: c026915c CTR: c0276d1c REGS: df43ba10 TRAP: 0300 Not tainted (4.20.0) MSR: 00009032 <EE,ME,IR,DR,RI> CR: 28228288 XER: 00000100 DAR: 00000024 DSISR: 40000000 GPR00: c026915c df43bac0 df439060 c0731524 df494700 00000000 c06e1c08 00000001 GPR08: 00000001 00000000 df5ff220 00001032 28228282 00000000 c0004ca4 00000000 GPR16: 00000000 00000000 00000000 c073144c dfffe064 c0731524 00000120 c0586108 GPR24: c073132c c073143c c073143c 00000000 c0731524 df67cd70 df494700 00000001 NIP [c02652f8] blk_mq_free_rqs+0x28/0xf8 LR [c026915c] blk_mq_sched_tags_teardown+0x58/0x84 Call Trace: [df43bac0] [c0045f50] flush_workqueue_prep_pwqs+0x178/0x1c4 (unreliable) [df43bae0] [c026915c] blk_mq_sched_tags_teardown+0x58/0x84 [df43bb00] [c02697f0] blk_mq_exit_sched+0x9c/0xb8 [df43bb20] [c0252794] elevator_exit+0x84/0xa4 [df43bb40] [c0256538] blk_exit_queue+0x30/0x50 [df43bb50] [c0256640] blk_cleanup_queue+0xe8/0x184 [df43bb70] [c034732c] swim3_attach+0x330/0x5f0 [df43bbb0] [c034fb24] macio_device_probe+0x58/0xec [df43bbd0] [c032ba88] really_probe+0x1e4/0x2f4 [df43bc00] [c032bd28] driver_probe_device+0x64/0x204 [df43bc20] [c0329ac4] bus_for_each_drv+0x60/0xac [df43bc50] [c032b824] __device_attach+0xe8/0x160 [df43bc80] [c032ab38] bus_probe_device+0xa0/0xbc [df43bca0] [c0327338] device_add+0x3d8/0x630 [df43bcf0] [c0350848] macio_add_one_device+0x444/0x48c [df43bd50] [c03509f8] macio_pci_add_devices+0x168/0x1bc [df43bd90] [c03500ec] macio_pci_probe+0xc0/0x10c [df43bda0] [c02ad884] pci_device_probe+0xd4/0x184 [df43bdd0] [c032ba88] really_probe+0x1e4/0x2f4 [df43be00] [c032bd28] driver_probe_device+0x64/0x204 [df43be20] [c032bfcc] __driver_attach+0x104/0x108 [df43be40] [c0329a00] bus_for_each_dev+0x64/0xb4 [df43be70] [c032add8] bus_add_driver+0x154/0x238 [df43be90] [c032ca24] driver_register+0x84/0x148 [df43bea0] [c0004aa0] do_one_initcall+0x40/0x188 [df43bf00] [c0690100] kernel_init_freeable+0x138/0x1d4 [df43bf30] [c0004cbc] kernel_init+0x18/0x10c [df43bf40] [c00121e4] ret_from_kernel_thread+0x14/0x1c Instruction dump: 5484d97e 4bfff4f4 9421ffe0 7c0802a6 bf410008 7c9e2378 90010024 8124005c 2f890000 419e0078 81230004 7c7c1b78 <81290024> 2f890000 419e0064 81440000 ---[ end trace 12025ab921a9784c ]--- Reverting commit8ccb8cb189("swim3: convert to blk-mq") resolves the problem. That commit added a struct blk_mq_tag_set to struct floppy_state and initialized it with a blk_mq_init_sq_queue() call. Unfortunately, there is a memset() in swim3_add_device() that subsequently clears the floppy_state struct. That means fs->tag_set->ops is a NULL pointer, and it gets dereferenced by blk_mq_free_rqs() which gets called in the request_irq() error path. Move the memset() to fix this bug. BTW, the request_irq() failure for the left mediabay floppy (fd1) is not a regression. I don't know why it happens. The right media bay floppy (fd0) works fine however. Reported-and-tested-by: Stan Johnson <userm57@yahoo.com> Fixes:8ccb8cb189("swim3: convert to blk-mq") Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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