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| author | Bjoern A. Zeeb <bz@FreeBSD.org> | 2021-06-09 18:53:16 +0000 |
|---|---|---|
| committer | Bjoern A. Zeeb <bz@FreeBSD.org> | 2021-06-18 21:20:10 +0000 |
| commit | 46ae23a4024b792c44a2b6c5f80429c40dac120b (patch) | |
| tree | a3356044972a19b1305208f4a9dadecfd5d32a68 | |
| parent | edfcdffefc1671b7688c8806ae1f59484954dcc7 (diff) | |
| download | src-46ae23a4024b792c44a2b6c5f80429c40dac120b.tar.gz src-46ae23a4024b792c44a2b6c5f80429c40dac120b.zip | |
LinuxKPI: avoid userret: Returning with with pinned thread
Some code manually calls local_bh_disable() and spin_lock() but
then calls spin_unlock_bh() (or vice versa).
Our code then calls local_bh_disable() again from spin_lock()
which means we have the thread pin count increased twice and that
means we get out of synch and are still pinned when returning to
user space.
Avoid this by adding the explicit local_bh_{enable,disable}() to
the spin_[un]lock_bh() versions.
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30711
| -rw-r--r-- | sys/compat/linuxkpi/common/include/linux/spinlock.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sys/compat/linuxkpi/common/include/linux/spinlock.h b/sys/compat/linuxkpi/common/include/linux/spinlock.h index 83f45b1a2a40..ca51fd23434c 100644 --- a/sys/compat/linuxkpi/common/include/linux/spinlock.h +++ b/sys/compat/linuxkpi/common/include/linux/spinlock.h @@ -66,6 +66,7 @@ typedef struct { #define spin_lock_bh(_l) do { \ spin_lock(_l); \ + local_bh_disable(); \ } while (0) #define spin_lock_irq(_l) do { \ @@ -80,6 +81,7 @@ typedef struct { } while (0) #define spin_unlock_bh(_l) do { \ + local_bh_enable(); \ spin_unlock(_l); \ } while (0) |