#21705: Segmentation Faults when using Swap on ar71xx (zram)
-----------------------+--------------------------------
Reporter: mt@… | Owner: developers
Type: defect | Status: new
Priority: normal | Milestone:
Component: kernel | Version: Chaos Calmer 15.05
Keywords: swap,zram |
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Hi,
when using zram-swap and memory usage is high random applications start to
crash. At first I suspected it's some problem with the zram Block device
that get's corrupted but I can write and read data just fine on the device
and I'm able to fill it with data and read that back without problems. So
the issue seems to be somewhere related to swapping.
The happens on current trunk (4.1.25) as well as current ChaosCalmer.
Here is a typical result with lots of segfaults (with
kernel.print-fatal-signals=1):
{{{
[ 223.902219] do_page_fault(): sending SIGSEGV to netifd for invalid
write access to 00000000
[ 223.910852] epc = 77398a6c in libc.so[7731c000+92000]
[ 223.916159] ra = 77398a6c in libc.so[7731c000+92000]
[ 223.921440]
[ 224.281923] potentially unexpected fatal signal 11.
[ 224.286990] CPU: 0 PID: 1110 Comm: netifd Not tainted 4.1.15 #2
[ 224.293176] task: 81932ef8 ti: 816f6000 task.ti: 816f6000
[ 224.298750] $ 0 : 00000000 00000000 00000003 00000000
[ 224.304450] $ 4 : 773a88ed ff456461 80808080 fefefeff
[ 224.309887] $ 8 : f73abb54 00000000 00004000 8eac4000
[ 224.315370] $12 : 0000000a 00000000 0000000e 00023ab1
[ 224.320808] $16 : 773a88ed 773abb55 7fbe7048 7fbe6f50
[ 224.326257] $20 : 00000000 773abb55 00000062 00400019
[ 224.331687] $24 : 00000000 7738d8d0
[ 224.337143] $28 : 773c6320 7fbe6ec8 7fbe7048 77398a6c
[ 224.342821] Hi : 0000003a
[ 224.345799] Lo : 00000012
[ 224.348782] epc : 77398a6c 0x77398a6c
[ 224.352815] ra : 77398a6c 0x77398a6c
[ 224.356776] Status: 0100f413 USER EXL IE
[ 224.360951] Cause : 0080000c
[ 224.363953] BadVA : 00000000
[ 224.366928] PrId : 0001974c (MIPS 74Kc)
[ 230.081537]
[ 230.081537] do_page_fault(): sending SIGSEGV to sh for invalid read
access from 00000000
[ 230.090122] epc = 00000000 in busybox[400000+46000]
[ 230.095227] ra = 00000000 in busybox[400000+46000]
[ 230.100289]
[ 230.791874] potentially unexpected fatal signal 11.
[ 230.796942] CPU: 0 PID: 3982 Comm: sh Not tainted 4.1.15 #2
[ 230.802763] task: 8071da18 ti: 81cc0000 task.ti: 81cc0000
[ 230.808342] $ 0 : 00000000 00000001 00000f8f 00000000
[ 230.814067] $ 4 : ffffffff 7fad75fc 00000000 00000000
[ 230.819506] $ 8 : 00000000 80064f20 803c9154 803244d8
[ 230.824962] $12 : 0000001a 00000013 0000000e 00000007
[ 230.830626] $16 : 00000000 00000000 00000000 00000000
[ 230.836100] $20 : 00000000 77fba000 7fad84f4 77fbd490
[ 230.841529] $24 : 00000001 77f936c0
[ 230.847122] $28 : 00000000 7fad75a8 00000000 00000000
[ 230.852606] Hi : 00000000
[ 230.855580] Lo : 00000007
[ 230.858556] epc : 00000000 (null)
[ 230.862363] ra : 00000000 (null)
[ 230.866143] Status: 0100f413 USER EXL IE
[ 230.870318] Cause : 00800008
[ 230.873317] BadVA : 00000000
[ 230.876449] PrId : 0001974c (MIPS 74Kc)
[ 244.728483] potentially unexpected fatal signal 11.
[ 244.733635] CPU: 0 PID: 3976 Comm: ubusd Not tainted 4.1.15 #2
[ 244.739663] task: 8071f430 ti: 81496000 task.ti: 81496000
[ 244.745275] $ 0 : 00000000 00000000 2462ffff 779ba020
[ 244.750739] $ 4 : 779ba000 00000001 779ba020 00000000
[ 244.756405] $ 8 : 00000000 0000f400 00000011 85000014
[ 244.761891] $12 : 00077469 00000000 00000000 6d656f75
[ 244.767322] $16 : 779b29b0 779ba000 77a590b0 77a57538
[ 244.772961] $20 : 77a54000 77a54000 7fdfaaf4 77a57490
[ 244.778398] $24 : 00000000 779d0560
[ 244.783873] $28 : 779ba020 7fdfaa30 00000000 7799dbf9
[ 244.789312] Hi : 00399e63
[ 244.792307] Lo : 49be433d
[ 244.795285] epc : 7799dce9 0x7799dce9
[ 244.799322] ra : 7799dbf9 0x7799dbf9
[ 244.803335] Status: 0100f413 USER EXL IE
[ 244.807510] Cause : 00800010
[ 244.810485] BadVA : 24630003
[ 244.813650] PrId : 0001974c (MIPS 74Kc)
[ 248.265148]
}}}
--
Ticket URL: <https://dev.openwrt.org/ticket/21705>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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