Revision 38860b2c8bb1b92f61396eb06a63adff916fc31d authored by John David Anglin on 08 November 2021, 21:48:16 UTC, committed by Helge Deller on 13 November 2021, 21:10:56 UTC
For years, there have been random segmentation faults in userspace on SMP PA-RISC machines. It occurred to me that this might be a problem in set_pte_at(). MIPS and some other architectures do cache flushes when installing PTEs with the present bit set. Here I have adapted the code in update_mmu_cache() to flush the kernel mapping when the kernel flush is deferred, or when the kernel mapping may alias with the user mapping. This simplifies calls to update_mmu_cache(). I also changed the barrier in set_pte() from a compiler barrier to a full memory barrier. I know this change is not sufficient to fix the problem. It might not be needed. I have had a few days of operation with 5.14.16 to 5.15.1 and haven't seen any random segmentation faults on rp3440 or c8000 so far. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Cc: stable@kernel.org # 5.12+
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File | Mode | Size |
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Makefile | -rw-r--r-- | 361 bytes |
compat.c | -rw-r--r-- | 2.2 KB |
ipc_sysctl.c | -rw-r--r-- | 6.3 KB |
mq_sysctl.c | -rw-r--r-- | 2.7 KB |
mqueue.c | -rw-r--r-- | 43.4 KB |
msg.c | -rw-r--r-- | 31.6 KB |
msgutil.c | -rw-r--r-- | 3.6 KB |
namespace.c | -rw-r--r-- | 5.1 KB |
sem.c | -rw-r--r-- | 63.2 KB |
shm.c | -rw-r--r-- | 42.8 KB |
syscall.c | -rw-r--r-- | 5.1 KB |
util.c | -rw-r--r-- | 23.6 KB |
util.h | -rw-r--r-- | 8.9 KB |
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