• Vasant Hegde's avatar
    iommu/amd: Fix Invalid wait context issue · 526606b0
    Vasant Hegde authored
    With commit c4cb2311 ("iommu/amd: Add support for enable/disable IOPF")
    we are hitting below issue. This happens because in IOPF enablement path
    it holds spin lock with irq disable and then tries to take mutex lock.
    
    dmesg:
    -----
    [    0.938739] =============================
    [    0.938740] [ BUG: Invalid wait context ]
    [    0.938742] 6.10.0-rc1+ #1 Not tainted
    [    0.938745] -----------------------------
    [    0.938746] swapper/0/1 is trying to lock:
    [    0.938748] ffffffff8c9f01d8 (&port_lock_key){....}-{3:3}, at: serial8250_console_write+0x78/0x4a0
    [    0.938767] other info that might help us debug this:
    [    0.938768] context-{5:5}
    [    0.938769] 7 locks held by swapper/0/1:
    [    0.938772]  #0: ffff888101a91310 (&group->mutex){+.+.}-{4:4}, at: bus_iommu_probe+0x70/0x160
    [    0.938790]  #1: ffff888101d1f1b8 (&domain->lock){....}-{3:3}, at: amd_iommu_attach_device+0xa5/0x700
    [    0.938799]  #2: ffff888101cc3d18 (&dev_data->lock){....}-{3:3}, at: amd_iommu_attach_device+0xc5/0x700
    [    0.938806]  #3: ffff888100052830 (&iommu->lock){....}-{2:2}, at: amd_iommu_iopf_add_device+0x3f/0xa0
    [    0.938813]  #4: ffffffff8945a340 (console_lock){+.+.}-{0:0}, at: _printk+0x48/0x50
    [    0.938822]  #5: ffffffff8945a390 (console_srcu){....}-{0:0}, at: console_flush_all+0x58/0x4e0
    [    0.938867]  #6: ffffffff82459f80 (console_owner){....}-{0:0}, at: console_flush_all+0x1f0/0x4e0
    [    0.938872] stack backtrace:
    [    0.938874] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.10.0-rc1+ #1
    [    0.938877] Hardware name: HP HP EliteBook 745 G3/807E, BIOS N73 Ver. 01.39 04/16/2019
    
    Fix above issue by re-arranging code in attach device path:
      - move device PASID/IOPF enablement outside lock in AMD IOMMU driver.
        This is safe as core layer holds group->mutex lock before calling
        iommu_ops->attach_dev.
    Reported-by: default avatarBorislav Petkov <bp@alien8.de>
    Reported-by: default avatarMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
    Reported-by: default avatarChris Bainbridge <chris.bainbridge@gmail.com>
    Fixes: c4cb2311 ("iommu/amd: Add support for enable/disable IOPF")
    Tested-by: default avatarBorislav Petkov <bp@alien8.de>
    Tested-by: default avatarChris Bainbridge <chris.bainbridge@gmail.com>
    Tested-by: default avatarMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
    Signed-off-by: default avatarVasant Hegde <vasant.hegde@amd.com>
    Link: https://lore.kernel.org/r/20240530084801.10758-1-vasant.hegde@amd.comSigned-off-by: default avatarJoerg Roedel <jroedel@suse.de>
    526606b0
iommu.c 93.8 KB