Created attachment 156541 [details] dmesg.log boot problems with all of the kernels 3.18 published so far: after the termination of the boot process, no sudo commands can be processed. There is no wifi. No access to "synaptic". This is for lubuntu-14.10 on dell e6500. "dmesg" produces the BUG "unable to handle kernel null pointer de - reference at ..." (see attached file) No such problems with any of the kernels 3.16 and 3.17. In particular, the machine runs well with 3.17.2 and 3.16.0-25.
Created attachment 156831 [details] b43: fix NULL pointer dereference in b43_phy_copy() The attached patch should fix your problem. The null pointer dereference you have was caused by a regression in 3.18. I hope this is the root cause of your problem.
(In reply to Hauke Mehrtens from comment #1) > Created attachment 156831 [details] > b43: fix NULL pointer dereference in b43_phy_copy() > > The attached patch should fix your problem. The null pointer dereference you > have was caused by a regression in 3.18. I hope this is the root cause of > your problem. thanks for the immediate reply! Meanwhile, I had confirmed that b43 is at the origin of the problem: I deactivated b43-fwcutter and the firmware -> following that, 14.10 boots well with al 3.18 kernels. Remaining "problem": how to use the attachment / patch (never done that before)? Any suggestion / link?
(In reply to volker_kempter from comment #2) > > Remaining "problem": how to use the attachment / patch (never done that > before)? > Any suggestion / link? you can modify the file /drivers/net/wireless/b43/phy_common.c by replacing this line : dev->phy.ops->phy_write(dev, destreg, dev->phy.ops->phy_read(dev, srcreg)); by this line : b43_phy_write(dev, destreg, b43_phy_read(dev, srcreg)); or you can use the program "diff" in order to apply the patch : http://fluxbb.org/docs/patching once the file has been modified you can follow the next step : - build your own kernel version with this modified source file ( /drivers/net/wireless/b43/phy_common.c ), you can follow this guide for ubuntu : https://help.ubuntu.com/community/Kernel/Compile
(In reply to Barto from comment #3) > (In reply to volker_kempter from comment #2) > > > > Remaining "problem": how to use the attachment / patch (never done that > > before)? > > Any suggestion / link? > > you can modify the file /drivers/net/wireless/b43/phy_common.c by replacing > this line : > > dev->phy.ops->phy_write(dev, destreg, > dev->phy.ops->phy_read(dev, srcreg)); > > by this line : > > b43_phy_write(dev, destreg, b43_phy_read(dev, srcreg)); > > or you can use the program "diff" in order to apply the patch : > > http://fluxbb.org/docs/patching > > once the file has been modified you can follow the next step : > > - build your own kernel version with this modified source file ( > /drivers/net/wireless/b43/phy_common.c ), you can follow this guide for > ubuntu : > > https://help.ubuntu.com/community/Kernel/Compile Bonjour! Thanks for your patience! I might try (download the kernel source with apt-get source to /usr/src (?), applying the patch to .../b43/phy_common.c -the easiest part-, building the kernel with fakeroot, install it). Good exercise, I suppose! I fell, however, that an updated kernel, supporting my hardware, will be available before I will be successful...
b43: fix NULL pointer dereference in b43_phy_copy(): an additional observation that could probably be of interest: The BUG"nullpointer dereference..." does not occur with the 3.18 kernels on the much older dell Latitude D505 under lubuntu-14.10 (and under Ubuntu-12.04). The only difference I can think of, is the BCM chip (4309 in the D505), but 4312 in the e6500 (who creates the boot problem). In both cases I'm using the b43-fwcutter.
(In reply to Hauke Mehrtens from comment #1) > Created attachment 156831 [details] > b43: fix NULL pointer dereference in b43_phy_copy() > > The attached patch should fix your problem. The null pointer dereference you > have was caused by a regression in 3.18. I hope this is the root cause of > your problem. I applied the attached patch to ../phy_common.c in kernel 3.18.0-rc3, built a new kernel from the modified source file: - boot successful without any obvious problems (in particular sudo and synaptic work) - WIFI with b43 works. Thanks for your help and advice to Barto and you!
kernel 3.18.0-rc4: for me, this version (-rc4) shows still the same problems as the previous versions. This is probably not too surprising because the patch has not yet been applied yet?
kernel 3.18.0-rc5: this version (-rc5) shows still the same problems as all the previous versions: not booting properly as soon as the b43 driver is activated.
The patch is currently in David Millers tree and should arrive in 3.18-rc6 https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=9c3a6670863033df421c8e46f79f383cf3a922ee
(In reply to Hauke Mehrtens from comment #9) > The patch is currently in David Millers tree and should arrive in 3.18-rc6 > > https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/ > ?id=9c3a6670863033df421c8e46f79f383cf3a922ee thanks for replying!
(In reply to Hauke Mehrtens from comment #9) > The patch is currently in David Millers tree and should arrive in 3.18-rc6 > > https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/ > ?id=9c3a6670863033df421c8e46f79f383cf3a922ee patch is in: 3.18-rc6 works normally and supports the b43 driver.