FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-18 15:09:53 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

MIPS: __raw_spin_lock() may spin forever on ticket wrap.

Browse Source 
If the lock is not acquired and has to spin *and* the second attempt
to acquire the lock fails, the delay time is not masked by the ticket
range mask.  If the ticket number wraps around to zero, the result is
that the lock sampling delay is essentially infinite (due to casting
-1 to an unsigned int).

The fix: Always mask the difference between my_ticket and the current
ticket value before calculating the delay.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2009-03-27 10:07:02 -07:00 committed by Ralf Baechle
parent f5fd02a33e
commit 0e6826c73c
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/mips/include/asm/spinlock.h
View File

@ -76,7 +76,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
"2: \n"
" .subsection 2 \n"
"4: andi %[ticket], %[ticket], 0x1fff \n"
"5: sll %[ticket], 5 \n"
" sll %[ticket], 5 \n"
" \n"
"6: bnez %[ticket], 6b \n"
" subu %[ticket], 1 \n"
@ -85,7 +85,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
" andi %[ticket], %[ticket], 0x1fff \n"
" beq %[ticket], %[my_ticket], 2b \n"
" subu %[ticket], %[my_ticket], %[ticket] \n"
" b 5b \n"
" b 4b \n"
" subu %[ticket], %[ticket], 1 \n"
" .previous \n"
" .set pop \n"
@ -113,7 +113,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
" ll %[ticket], %[ticket_ptr] \n"
" \n"
"4: andi %[ticket], %[ticket], 0x1fff \n"
"5: sll %[ticket], 5 \n"
" sll %[ticket], 5 \n"
" \n"
"6: bnez %[ticket], 6b \n"
" subu %[ticket], 1 \n"
@ -122,7 +122,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
" andi %[ticket], %[ticket], 0x1fff \n"
" beq %[ticket], %[my_ticket], 2b \n"
" subu %[ticket], %[my_ticket], %[ticket] \n"
" b 5b \n"
" b 4b \n"
" subu %[ticket], %[ticket], 1 \n"
" .previous \n"
" .set pop \n"