On Tue, Dec 17, 2019 at 01:55:27PM +0200, Alexander Shishkin wrote:
Commit 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger window switch") adds a NULL pointer dereference in the case when there are no windows allocated:
Commit ids should only be specified in 12 digits, not 13 :)
BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 1 SMP CPU: 5 PID: 1110 Comm: bash Not tainted 5.5.0-rc1+ #1 RIP: 0010:msc_win_switch+0xa/0x80 [intel_th_msu] Call Trace: ? win_switch_store+0x9b/0xc0 [intel_th_msu] dev_attr_store+0x17/0x30 sysfs_kf_write+0x3e/0x50 kernfs_fop_write+0xda/0x1b0 __vfs_write+0x1b/0x40 vfs_write+0xb9/0x1a0 ksys_write+0x67/0xe0 __x64_sys_write+0x1a/0x20 do_syscall_64+0x57/0x1d0 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix that by disallowing window switching with multiwindow buffers without windows.
Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Fixes: 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger window switch")
Same here.
I can go edit it by hand...